Trying to write letters like ä or ü using XeLaTeX?

Question

As I pre-write my thesis in Word I would appreciate to make a direct copy&paste into Kile. More when writting directly in Kile using something like \"u makes the text seems unstructured.

I know some way to use \inputenc, however as I am using XeLaTeX this does not work.

Is there some other way to write ä or ü directly?

I already tried using \usepackage[T1]{fontenc} but the characters are not shown.

My part of the preamble:

%---------------------------------------------------------------------------- ------------
%   Encoding und Language
%----------------------------------------------------------------------------------------
\XeTeXinputencoding latin1
\usepackage[T1]{fontenc}                            
\usepackage{polyglossia}
\setdefaultlanguage[spelling=new]{german}
\setotherlanguage{english}
\usepackage{csquotes}   
%----------------------------------------------------------------------------------------
%   Fonts
%----------------------------------------------------------------------------------------

\usepackage{fontspec}

Thank you in advance for your help.

EDIT:

New MWE:

\documentclass[10pt]{article}
\usepackage{fontspec}
\begin{document}
test äö ß dfß ü 
\end{document}

Compiled with XeLaTeX, the Output PDF only shows Test without the special characters

Full Log:

This is XeTeX, Version 3.14159265-2.6-0.999991 (MiKTeX 2.9.7250 64-bit) (preloaded format=xelatex 2020.1.16)  21 JAN 2020 21:37
entering extended mode
**./Test.tex
(Test.tex
LaTeX2e <2019-10-01> patch level 3
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/memoir\memoir.cls"
Document Class: memoir 2019/11/21 v3.7j configurable book, report, article docu
ment class
\onelineskip=\skip41
\lxvchars=\skip42
\xlvchars=\skip43
\@memcnta=\count80
\c@@memmarkcntra=\count81
LaTeX Info: Redefining \InputIfFileExists on input line 140.
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/generic/iftex\iftex.sty"
Package: iftex 2019/11/07 v1.0c TeX engine tests
)
\stockheight=\skip44
\stockwidth=\skip45
\trimtop=\skip46
\trimedge=\skip47
 ("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/memoir\mem10.clo"
File: mem10.clo 2008/01/30 v0.3 memoir class 10pt size option
)
\binding=\skip48
\spinemargin=\skip49
\foremargin=\skip50
\uppermargin=\skip51
\lowermargin=\skip52
\headdrop=\skip53
\normalrulethickness=\skip54
\mem@maxheadheight=\skip55
\mem@maxfootheight=\skip56
\headwidth=\skip57
\c@storedpagenumber=\count82
\memPD=\dimen102
\m@mabparskip=\skip58
\thanksmarkwidth=\skip59
\thanksmarksep=\skip60
\droptitle=\skip61
\c@book=\count83
\c@part=\count84
\c@chapter=\count85
\c@section=\count86
\c@subsection=\count87
\c@subsubsection=\count88
\c@paragraph=\count89
\c@subparagraph=\count90
\beforechapskip=\skip62
\midchapskip=\skip63
\afterchapskip=\skip64
\chapindent=\skip65
\bottomsectionskip=\skip66
\secindent=\skip67
\beforesecskip=\skip68
\aftersecskip=\skip69
\subsecindent=\skip70
\beforesubsecskip=\skip71
\aftersubsecskip=\skip72
\subsubsecindent=\skip73
\beforesubsubsecskip=\skip74
\aftersubsubsecskip=\skip75
\paraindent=\skip76
\beforeparaskip=\skip77
\afterparaskip=\skip78
\subparaindent=\skip79
\beforesubparaskip=\skip80
\aftersubparaskip=\skip81
\pfbreakskip=\skip82
\c@@ppsavesec=\count91
\c@@ppsaveapp=\count92
\ragrparindent=\dimen103
\everylistparindent=\dimen104
\parsepi=\skip83
\topsepi=\skip84
\itemsepi=\skip85
\parsepii=\skip86
\topsepii=\skip87
\topsepiii=\skip88
\itemsepii=\skip89
\itemsepiii=\skip90
\partopsepii=\skip91
\partopsepiii=\skip92
\m@msavetopsep=\skip93
\m@msavepartopsep=\skip94
\@enLab=\toks14
\abstitleskip=\skip95
\absleftindent=\skip96
\abs@leftindent=\dimen105
\absrightindent=\skip97
\absparindent=\skip98
\absparsep=\skip99
\c@vslineno=\count93
\c@poemline=\count94
\c@modulo@vs=\count95
\c@memfvsline=\count96
\vleftskip=\skip100
\vrightskip=\skip101
\stanzaskip=\skip102
\versewidth=\skip103
\vgap=\skip104
\vindent=\skip105
\vleftmargin=\dimen106
\c@verse=\count97
\c@chrsinstr=\count98
\beforepoemtitleskip=\skip106
\afterpoemtitleskip=\skip107
\c@poem=\count99
\beforePoemTitleskip=\skip108
\midPoemTitleskip=\skip109
\afterPoemTitleskip=\skip110
 ("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/tools\array.sty"
Package: array 2019/08/31 v2.4l Tabular extension package (FMi)
\col@sep=\dimen107
\ar@mcellbox=\box27
\extrarowheight=\dimen108
\NC@list=\toks15
\extratabsurround=\skip111
\backup@length=\skip112
\ar@cellbox=\box28
)
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/tools\dcolumn.sty"
Package: dcolumn 2014/10/28 v1.06 decimal alignment package (DPC)
)
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/tools\delarray.sty
"
Package: delarray 2014/10/28 v1.01 array delimiter package (DPC)
)
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/tools\tabularx.sty
"
Package: tabularx 2016/02/03 v2.11b `tabularx' package (DPC)
\TX@col@width=\dimen109
\TX@old@table=\dimen110
\TX@old@col=\dimen111
\TX@target=\dimen112
\TX@delta=\dimen113
\TX@cols=\count100
\TX@ftn=\toks16
)
\heavyrulewidth=\dimen114
\lightrulewidth=\dimen115
\cmidrulewidth=\dimen116
\belowrulesep=\dimen117
\belowbottomsep=\dimen118
\aboverulesep=\dimen119
\abovetopsep=\dimen120
\cmidrulesep=\dimen121
\cmidrulekern=\dimen122
\defaultaddspace=\dimen123
\@cmidla=\count101
\@cmidlb=\count102
\@aboverulesep=\dimen124
\@belowrulesep=\dimen125
\@thisruleclass=\count103
\@lastruleclass=\count104
\@thisrulewidth=\dimen126
\ctableftskip=\skip113
\ctabrightskip=\skip114
\abovecolumnspenalty=\count105
\@linestogo=\count106
\@cellstogo=\count107
\@cellsincolumn=\count108
\crtok=\toks17
\@mincolumnwidth=\dimen127
\c@newflo@tctr=\count109
\mem@margin@floatbox=\box29
\@contcwidth=\skip115
\@contindw=\skip116
\abovecaptionskip=\skip117
\belowcaptionskip=\skip118
\subfloattopskip=\skip119
\subfloatcapskip=\skip120
\subfloatcaptopadj=\skip121
\subfloatbottomskip=\skip122
\subfloatlabelskip=\skip123
\subfloatcapmargin=\dimen128
\c@@contsubnum=\count110
\m@mscap@capbox=\box30
\m@mscap@fbox=\box31
\sidecapsep=\dimen129
\sidecapwidth=\dimen130
\m@m@tempdima=\dimen131
\m@mscapraise=\dimen132
\sidecapraise=\dimen133
\m@mscapmainwidth=\dimen134
\m@mscaplkern=\dimen135
\beforeepigraphskip=\skip124
\afterepigraphskip=\skip125
\epigraphwidth=\skip126
\epigraphrule=\skip127
LaTeX Info: Redefining \em on input line 7662.
LaTeX Info: Redefining \emph on input line 7670.
\tocentryskip=\skip128
\tocbaseline=\skip129
\cftparskip=\skip130
\cftbeforebookskip=\skip131
\cftbookindent=\dimen136
\cftbooknumwidth=\dimen137
\cftbeforepartskip=\skip132
\cftpartindent=\skip133
\cftpartnumwidth=\skip134
\cftbeforechapterskip=\skip135
\cftchapterindent=\skip136
\cftchapternumwidth=\skip137
\cftbeforesectionskip=\skip138
\cftsectionindent=\skip139
\cftsectionnumwidth=\skip140
\cftbeforesubsectionskip=\skip141
\cftsubsectionindent=\skip142
\cftsubsectionnumwidth=\skip143
\cftbeforesubsubsectionskip=\skip144
\cftsubsubsectionindent=\skip145
\cftsubsubsectionnumwidth=\skip146
\cftbeforeparagraphskip=\skip147
\cftparagraphindent=\skip148
\cftparagraphnumwidth=\skip149
\cftbeforesubparagraphskip=\skip150
\cftsubparagraphindent=\skip151
\cftsubparagraphnumwidth=\skip152
\prechapterprecisshift=\dimen138
\c@maxsecnumdepth=\count111
\bibindent=\dimen139
\bibitemsep=\skip153
\indexcolsep=\skip154
\indexrule=\skip155
\indexmarkstyle=\toks18
\@indexbox=\insert199
\glossarycolsep=\dimen140
\glossaryrule=\dimen141
\sideparvshift=\skip156
\sideins=\insert198
\sidebartopsep=\skip157
\sidebarhsep=\skip158
\sidebarvsep=\skip159
\sidebarwidth=\skip160
\footmarkwidth=\skip161
\footmarksep=\skip162
\footparindent=\skip163
\footinsdim=\skip164
\footinsv@r=\insert197
\@mpfootinsv@r=\insert196
\m@m@k=\count112
\m@m@h=\dimen142
\m@mipn@skip=\skip165
\sidefootins=\insert195
\sidefootadjust=\skip166
\sidefootheight=\skip167
\sidefoothsep=\skip168
\sidefootvsep=\skip169
\sidefootwidth=\skip170
\m@mdownsf=\skip171
\c@sidefootnote=\count113
\sidefootmarkwidth=\skip172
\sidefootmarksep=\skip173
\sidefootparindent=\skip174
\c@pagenote=\count114
\c@pagenoteshadow=\count115
\mem@pn@lastkern=\skip175
\every@verbatim=\toks19
\afterevery@verbatim=\toks20
\verbatim@line=\toks21
\tab@position=\count116
\verbatim@in@stream=\read1
\verbatimindent=\skip176
\verbatim@out=\write3
\bvboxsep=\skip177
\c@memfbvline=\count117
\c@bvlinectr=\count118
\bvnumlength=\skip178
\fb@frw=\dimen143
\fb@frh=\dimen144
\FrameRule=\dimen145
\FrameSep=\dimen146
\c@cp@cntr=\count119
LaTeX Info: Redefining \: on input line 12187.
LaTeX Info: Redefining \! on input line 12189.
\c@ism@mctr=\count120
\c@xsm@mctr=\count121
\c@csm@mctr=\count122
\c@ksm@mctr=\count123
\c@xksm@mctr=\count124
\c@cksm@mctr=\count125
\c@msm@mctr=\count126
\c@xmsm@mctr=\count127
\c@cmsm@mctr=\count128
\c@bsm@mctr=\count129
\c@workm@mctr=\count130
\c@sheetsequence=\count131
\c@lastsheet=\count132
\c@lastpage=\count133

("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/textcase\textcase.
sty"
Package: textcase 2019/09/14 v1.00 Text only upper/lower case changing (DPC)
)
\c@figure=\count134
\c@lofdepth=\count135
\cftbeforefigureskip=\skip179
\cftfigureindent=\skip180
\cftfigurenumwidth=\skip181
\c@table=\count136
\c@lotdepth=\count137
\cftbeforetableskip=\skip182
\cfttableindent=\skip183
\cfttablenumwidth=\skip184
Package abstract [2008/07/23] emulated by memoir.
Package appendix [2008/07/23] emulated by memoir.
Package booktabs [2016/05/16] emulated by memoir.
Package ccaption [2008/07/23] emulated by memoir.
Package changepage [2008/07/23] emulated by memoir.
Package chngcntr [2008/07/23] emulated by memoir.
Package chngpage [2008/07/23] emulated by memoir.
Package crop emulated by memoir.
Package enumerate [2008/07/23] emulated by memoir.
Package epigraph [2008/07/23] emulated by memoir.
Package ifmtarg [2008/07/23] emulated by memoir.
Package index [2008/07/23] emulated by memoir.
Package makeidx [2008/07/23] emulated by memoir.
Package moreverb [2008/07/23] emulated by memoir.
Package mparhack [2008/07/23] emulated by memoir.
Package needspace [2008/07/23] emulated by memoir.
Package newfile [2008/07/23] emulated by memoir.
Package nextpage [2008/07/23] emulated by memoir.
Package pagenote [2008/07/23] emulated by memoir.
Package parskip [2008/07/23] emulated by memoir.
Package patchcmd [2008/07/23] emulated by memoir.
Package setspace [2008/07/23] emulated by memoir.
Package shortvrb [2008/07/23] emulated by memoir.
Package showidx [2008/07/23] emulated by memoir.
Package titleref [2008/07/23] emulated by memoir.
Package titling [2008/07/23] emulated by memoir.
Package tocbibind [2008/07/23] emulated by memoir.
Package tocloft [2008/07/23] emulated by memoir.
Package tocvsec2 [2008/07/23] emulated by memoir.
Package verbatim [2008/07/23] emulated by memoir.
Package verse [2008/07/23] emulated by memoir.
)
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/fontspec\fontspec.
sty"
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/l3packages/xparse\
xparse.sty"
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/l3kernel\expl3.sty
"
Package: expl3 2020-01-12 L3 programming layer (loader) 

("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/l3kernel\expl3-cod
e.tex"
Package: expl3 2020-01-12 L3 programming layer (code)
\c_max_int=\count138
\l_tmpa_int=\count139
\l_tmpb_int=\count140
\g_tmpa_int=\count141
\g_tmpb_int=\count142
\l__seq_internal_a_int=\count143
\l__seq_internal_b_int=\count144
\g__kernel_prg_map_int=\count145
\c__ior_term_noprompt_ior=\count146
\c_log_iow=\count147
\l_iow_line_count_int=\count148
\l__iow_line_target_int=\count149
\l__iow_one_indent_int=\count150
\l__iow_indent_int=\count151
\c_zero_dim=\dimen147
\c_max_dim=\dimen148
\l_tmpa_dim=\dimen149
\l_tmpb_dim=\dimen150
\g_tmpa_dim=\dimen151
\g_tmpb_dim=\dimen152
\c_zero_skip=\skip185
\c_max_skip=\skip186
\l_tmpa_skip=\skip187
\l_tmpb_skip=\skip188
\g_tmpa_skip=\skip189
\g_tmpb_skip=\skip190
\c_zero_muskip=\muskip10
\c_max_muskip=\muskip11
\l_tmpa_muskip=\muskip12
\l_tmpb_muskip=\muskip13
\g_tmpa_muskip=\muskip14
\g_tmpb_muskip=\muskip15
\l_keys_choice_int=\count152
\l__intarray_loop_int=\count153
\c__intarray_sp_dim=\dimen153
\g__intarray_font_int=\count154
\c__fp_leading_shift_int=\count155
\c__fp_middle_shift_int=\count156
\c__fp_trailing_shift_int=\count157
\c__fp_big_leading_shift_int=\count158
\c__fp_big_middle_shift_int=\count159
\c__fp_big_trailing_shift_int=\count160
\c__fp_Bigg_leading_shift_int=\count161
\c__fp_Bigg_middle_shift_int=\count162
\c__fp_Bigg_trailing_shift_int=\count163
\g__fp_array_int=\count164
\l__fp_array_loop_int=\count165
\l__sort_length_int=\count166
\l__sort_min_int=\count167
\l__sort_top_int=\count168
\l__sort_max_int=\count169
\l__sort_true_max_int=\count170
\l__sort_block_int=\count171
\l__sort_begin_int=\count172
\l__sort_end_int=\count173
\l__sort_A_int=\count174
\l__sort_B_int=\count175
\l__sort_C_int=\count176
\l__str_internal_int=\count177
\l__tl_analysis_normal_int=\count178
\l__tl_analysis_index_int=\count179
\l__tl_analysis_nesting_int=\count180
\l__tl_analysis_type_int=\count181
\l__regex_internal_a_int=\count182
\l__regex_internal_b_int=\count183
\l__regex_internal_c_int=\count184
\l__regex_balance_int=\count185
\l__regex_group_level_int=\count186
\l__regex_mode_int=\count187
\c__regex_cs_in_class_mode_int=\count188
\c__regex_cs_mode_int=\count189
\l__regex_catcodes_int=\count190
\l__regex_default_catcodes_int=\count191
\c__regex_catcode_L_int=\count192
\c__regex_catcode_O_int=\count193
\c__regex_catcode_A_int=\count194
\c__regex_all_catcodes_int=\count266
\l__regex_show_lines_int=\count267
\l__regex_min_state_int=\count268
\l__regex_max_state_int=\count269
\l__regex_left_state_int=\count270
\l__regex_right_state_int=\count271
\l__regex_capturing_group_int=\count272
\l__regex_min_pos_int=\count273
\l__regex_max_pos_int=\count274
\l__regex_curr_pos_int=\count275
\l__regex_start_pos_int=\count276
\l__regex_success_pos_int=\count277
\l__regex_curr_char_int=\count278
\l__regex_curr_catcode_int=\count279
\l__regex_last_char_int=\count280
\l__regex_case_changed_char_int=\count281
\l__regex_curr_state_int=\count282
\l__regex_step_int=\count283
\l__regex_min_active_int=\count284
\l__regex_max_active_int=\count285
\l__regex_replacement_csnames_int=\count286
\l__regex_match_count_int=\count287
\l__regex_min_submatch_int=\count288
\l__regex_submatch_int=\count289
\l__regex_zeroth_submatch_int=\count290
\g__regex_trace_regex_int=\count291
\c_empty_box=\box32
\l_tmpa_box=\box33
\l_tmpb_box=\box34
\g_tmpa_box=\box35
\g_tmpb_box=\box36
\l__box_top_dim=\dimen154
\l__box_bottom_dim=\dimen155
\l__box_left_dim=\dimen156
\l__box_right_dim=\dimen157
\l__box_top_new_dim=\dimen158
\l__box_bottom_new_dim=\dimen159
\l__box_left_new_dim=\dimen160
\l__box_right_new_dim=\dimen161
\l__box_internal_box=\box37
\l__coffin_internal_box=\box38
\l__coffin_internal_dim=\dimen162
\l__coffin_offset_x_dim=\dimen163
\l__coffin_offset_y_dim=\dimen164
\l__coffin_x_dim=\dimen165
\l__coffin_y_dim=\dimen166
\l__coffin_x_prime_dim=\dimen167
\l__coffin_y_prime_dim=\dimen168
\c_empty_coffin=\box39
\l__coffin_aligned_coffin=\box40
\l__coffin_aligned_internal_coffin=\box41
\l_tmpa_coffin=\box42
\l_tmpb_coffin=\box43
\g_tmpa_coffin=\box44
\g_tmpb_coffin=\box45
\l__coffin_bounding_shift_dim=\dimen169
\l__coffin_left_corner_dim=\dimen170
\l__coffin_right_corner_dim=\dimen171
\l__coffin_bottom_corner_dim=\dimen172
\l__coffin_top_corner_dim=\dimen173
\l__coffin_scaled_total_height_dim=\dimen174
\l__coffin_scaled_width_dim=\dimen175
\c__coffin_empty_coffin=\box46
\l__coffin_display_coffin=\box47
\l__coffin_display_coord_coffin=\box48
\l__coffin_display_pole_coffin=\box49
\l__coffin_display_offset_dim=\dimen176
\l__coffin_display_x_dim=\dimen177
\l__coffin_display_y_dim=\dimen178
\g__char_data_ior=\read2

("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/l3kernel\l3depreca
tion.def"
File: l3deprecation.def 2019-04-06 v L3 Deprecated functions
))
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/l3backend\l3backen
d-xdvipdfmx.def"
File: l3backend-xdvipdfmx.def 2019-04-06 L3 backend support: xdvipdfmx
\g__graphics_track_int=\count292
\l__pdf_internal_box=\box50
\g__pdf_backend_object_int=\count293
\g__pdf_backend_annotation_int=\count294
))
Package: xparse 2020-01-12 L3 Experimental document command parser
\l__xparse_current_arg_int=\count295
\g__xparse_grabber_int=\count296
\l__xparse_m_args_int=\count297
\l__xparse_v_nesting_int=\count298
)
Package: fontspec 2020/01/09 v2.7e Font selection for XeLaTeX and LuaLaTeX

("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/fontspec\fontspec-
xetex.sty"
Package: fontspec-xetex 2020/01/09 v2.7e Font selection for XeLaTeX and LuaLaTe
X
\l__fontspec_script_int=\count299
\l__fontspec_language_int=\count300
\l__fontspec_strnum_int=\count301
\l__fontspec_tmp_int=\count302
\l__fontspec_tmpa_int=\count303
\l__fontspec_tmpb_int=\count304
\l__fontspec_tmpc_int=\count305
\l__fontspec_em_int=\count306
\l__fontspec_emdef_int=\count307
\l__fontspec_strong_int=\count308
\l__fontspec_strongdef_int=\count309
\l__fontspec_tmpa_dim=\dimen179
\l__fontspec_tmpb_dim=\dimen180
\l__fontspec_tmpc_dim=\dimen181

("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/base\fontenc.sty"
Package: fontenc 2018/08/11 v2.0j Standard LaTeX package

("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/base\tuenc.def"
File: tuenc.def 2018/08/11 v2.0j Standard LaTeX file
LaTeX Font Info:    Redeclaring font encoding TU on input line 82.
))
("C:\Users\sebir\AppData\Local\Programs\MiKTeX 2.9\tex/latex/fontspec\fontspec.
cfg")
LaTeX Info: Redefining \itshape on input line 4120.
LaTeX Info: Redefining \slshape on input line 4120.
LaTeX Info: Redefining \scshape on input line 4120.
LaTeX Info: Redefining \upshape on input line 4120.
LaTeX Info: Redefining \em on input line 4120.
LaTeX Info: Redefining \emph on input line 4120.
)) (Test.aux)
\openout1 = `Test.aux'.

LaTeX Font Info:    Checking defaults for OML/cmm/m/it on input line 10.
LaTeX Font Info:    ... okay on input line 10.
LaTeX Font Info:    Checking defaults for T1/cmr/m/n on input line 10.
LaTeX Font Info:    ... okay on input line 10.
LaTeX Font Info:    Checking defaults for OT1/cmr/m/n on input line 10.
LaTeX Font Info:    ... okay on input line 10.
LaTeX Font Info:    Checking defaults for OMS/cmsy/m/n on input line 10.
LaTeX Font Info:    ... okay on input line 10.
LaTeX Font Info:    Checking defaults for TU/lmr/m/n on input line 10.
LaTeX Font Info:    ... okay on input line 10.
LaTeX Font Info:    Checking defaults for OMX/cmex/m/n on input line 10.
LaTeX Font Info:    ... okay on input line 10.
LaTeX Font Info:    Checking defaults for U/cmr/m/n on input line 10.
LaTeX Font Info:    ... okay on input line 10.

Package fontspec Info: Adjusting the maths setup (use [no-math] to avoid
(fontspec)             this).

\symlegacymaths=\mathgroup4
LaTeX Font Info:    Overwriting symbol font `legacymaths' in version `bold'
(Font)                  OT1/cmr/m/n --> OT1/cmr/bx/n on input line 10.
LaTeX Font Info:    Redeclaring math accent \acute on input line 10.
LaTeX Font Info:    Redeclaring math accent \grave on input line 10.
LaTeX Font Info:    Redeclaring math accent \ddot on input line 10.
LaTeX Font Info:    Redeclaring math accent \tilde on input line 10.
LaTeX Font Info:    Redeclaring math accent \bar on input line 10.
LaTeX Font Info:    Redeclaring math accent \breve on input line 10.
LaTeX Font Info:    Redeclaring math accent \check on input line 10.
LaTeX Font Info:    Redeclaring math accent \hat on input line 10.
LaTeX Font Info:    Redeclaring math accent \dot on input line 10.
LaTeX Font Info:    Redeclaring math accent \mathring on input line 10.
LaTeX Font Info:    Redeclaring math symbol \colon on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Gamma on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Delta on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Theta on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Lambda on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Xi on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Pi on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Sigma on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Upsilon on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Phi on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Psi on input line 10.
LaTeX Font Info:    Redeclaring math symbol \Omega on input line 10.
LaTeX Font Info:    Redeclaring math symbol \mathdollar on input line 10.
LaTeX Font Info:    Redeclaring symbol font `operators' on input line 10.
LaTeX Font Info:    Encoding `OT1' has changed to `TU' for symbol font
(Font)              `operators' in the math version `normal' on input line 10.
LaTeX Font Info:    Overwriting symbol font `operators' in version `normal'
(Font)                  OT1/cmr/m/n --> TU/lmr/m/n on input line 10.
LaTeX Font Info:    Encoding `OT1' has changed to `TU' for symbol font
(Font)              `operators' in the math version `bold' on input line 10.
LaTeX Font Info:    Overwriting symbol font `operators' in version `bold'
(Font)                  OT1/cmr/bx/n --> TU/lmr/m/n on input line 10.
LaTeX Font Info:    Overwriting symbol font `operators' in version `normal'
(Font)                  TU/lmr/m/n --> TU/lmr/m/n on input line 10.
LaTeX Font Info:    Overwriting math alphabet `\mathit' in version `normal'
(Font)                  OT1/cmr/m/it --> TU/lmr/m/it on input line 10.
LaTeX Font Info:    Overwriting math alphabet `\mathbf' in version `normal'
(Font)                  OT1/cmr/bx/n --> TU/lmr/bx/n on input line 10.
LaTeX Font Info:    Overwriting math alphabet `\mathsf' in version `normal'
(Font)                  OT1/cmss/m/n --> TU/lmss/m/n on input line 10.
LaTeX Font Info:    Overwriting math alphabet `\mathtt' in version `normal'
(Font)                  OT1/cmtt/m/n --> TU/lmtt/m/n on input line 10.
LaTeX Font Info:    Overwriting symbol font `operators' in version `bold'
(Font)                  TU/lmr/m/n --> TU/lmr/bx/n on input line 10.
LaTeX Font Info:    Overwriting math alphabet `\mathit' in version `bold'
(Font)                  OT1/cmr/bx/it --> TU/lmr/bx/it on input line 10.
LaTeX Font Info:    Overwriting math alphabet `\mathsf' in version `bold'
(Font)                  OT1/cmss/bx/n --> TU/lmss/bx/n on input line 10.
LaTeX Font Info:    Overwriting math alphabet `\mathtt' in version `bold'
(Font)                  OT1/cmtt/m/n --> TU/lmtt/bx/n on input line 10.
Invalid UTF-8 byte or sequence at line 11 replaced by U+FFFD.
Invalid UTF-8 byte or sequence at line 11 replaced by U+FFFD.
Invalid UTF-8 byte or sequence at line 11 replaced by U+FFFD.
Invalid UTF-8 byte or sequence at line 11 replaced by U+FFFD.
Invalid UTF-8 byte or sequence at line 11 replaced by U+FFFD.
Missing character: There is no � in font [lmroman10-regular]:mapping=tex-text;!
Missing character: There is no � in font [lmroman10-regular]:mapping=tex-text;!
Missing character: There is no � in font [lmroman10-regular]:mapping=tex-text;!
Missing character: There is no � in font [lmroman10-regular]:mapping=tex-text;!
Missing character: There is no � in font [lmroman10-regular]:mapping=tex-text;!
 [1

] (Test.aux) ) 
Here is how much of TeX's memory you used:
 17903 strings out of 427233
 361810 string characters out of 3141341
 451671 words of memory out of 3000000
 22419 multiletter control sequences out of 15000+200000
 532386 words of font info for 30 fonts, out of 3000000 for 9000
 1348 hyphenation exceptions out of 8191
 45i,10n,42p,321b,2146s stack positions out of 5000i,500n,10000p,200000b,50000s

Output written on Test.pdf (1 page).

Answer 1

Delete these lines

\XeTeXinputencoding latin1
\usepackage[T1]{fontenc}

the first one make the input be latin1 rather than the UTF-8 that is the default in xetex and this site almost anywhere else. Using latin1 with xetex is tricky and completely unnecessary, when you cut and paste text from other systems (eg the examples on this website) it will be carried as utf-8 usually.

Never use \usepackage[T1]{fontenc} with xelatex that forces the use of legacy 8-bit fonts so undoing most of the benefits of xetex which is to give access to Unicode fonts, and hypehantion will be incorrect as the xelatex format does not load hyphenation tables for T1 encoding.

Without those lines you should get the default behaviour of UTF-8 input and Unicode (TU) encoded fonts, so ä and ü can just be used as normal characters.

\documentclass{article}

\begin{document}

so ä and ü can just be used as normal characters.

\end{document}