I have already drawn a block diagram, but I would like to add some special symbols/figures such as a markov model, some dashed lines, list of characters in a specific place, and the waveform as shown in the picture below.
Here also goes the original picture from which I got my inspiration from. I would like to have a proportional size of the new elements as the original one (they are not scaled since I did not know how to do so) Thanks in advance in any help can be given!
My code so far:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{fit,arrows,calc,positioning,shapes, shadows}
\usetikzlibrary{tikzmark,calc,decorations.pathreplacing}
\begin{document}
\begin{figure}[h]
\centering
\begin{tikzpicture}[node distance=1.5cm]
\node (speech) {Speech};
\node [block, right of=speech, xshift=1.2cm] (feat) {Feature extraction};
\node [block, right of=feat, xshift=3cm] (dec) {Decoder};
\node [block, below of=dec, xshift=2.2cm, yshift=-0.5cm] (LM) {Language model};
\node at (LM.north) [above, text width=3cm, align=center] {Sentence level matcher};
\node [block, left of=LM, xshift=-2.2cm] (lex) {Lexicon};
\node at (lex.north) [above, text width=3cm, align=center] {Word-level matcher};
\coordinate (RSmid) at ($(LM.north east)!0.5!(lex.north west)$);
\coordinate (RSmid2) at ($(LM.south east)!0.5!(lex.south west)$);
\node [block, above of=dec, yshift=0.5cm] (acous) {Acoustic Model};
\node [right of= dec, xshift=3.1cm](txt) {Text};
\path [l] (feat) -- (dec);
\path [l] (lex) -| ([xshift=-1cm]dec);
\draw (acous) edge [auto=left] node {Phone-matcher level} (dec);
\path [l] (LM) -| ([xshift=1cm]dec);
\path [l] (dec) -- (txt);
\path [l] (speech.east) -- (feat);
\end{tikzpicture}
\end{figure}
\end{document}