How to reduce the number of hyphenation?

Question

Sometimes, assume our document contain many long words, TeX may generate some hyphenation at the end of line. But it really hinder our smooth reading. Although I know we can add the hyphenation rule at the preamble. It can't reduce hyphenation number but effect the hyphenation position. It is said that microtype package can give us more compact output. But it require expert level to tuning the parameter.

Answer 1

Some time ago, I wanted to deactivate hyphenation completely (without switching to \raggedright).

I found out that setting \pretolerance=10000 turns off the complete hyphenation mechanism: it tells TeX to not even look for hyphenation positions.

In addition, there is the parameter \hyphenpenalty. For example, \hyphenpenalty=10000 will (probably) also suppress hyphenation.

Naturally, forbidding hyphenation might cause underfull/overfull lines. That's why I added \tolerance=2000 \emergencystretch=10pt. The \tolerance parameter controls how much white space TeX considers to be "acceptable"; and the \emergencystretch configures TeX to use at most 10pt of additional white space per line in order to avoid underfull/overfull lines.

My solution to suppress hyphenation completely was

\pretolerance=10000
\tolerance=2000 
\emergencystretch=10pt

Now, I am aware that you expressed doubts on "tuning complicated parameters". But I encourage you to experiment with \pretolerance and/or \hyphenpenalty in combination with my suggestions for \tolerance and \emergencystretch.

The value 10000 is special in TeX, it means "disable this feature" - it is kind of "black or white". I would expect that any value between 0 and 10000 (exclusive) will "reduce" the number of hyphenations (i.e. a "grayshade").

According to my notes, I stumbled over the details on the mentioned parameters in Knuth, D.: Computers & Typesetting – The TEXbook. AddisonWesley, 1986 on page 96.

Answer 2

Disabling hyphenation entirely frequently creates more problems than it solves. You may want to fiddle with the \lefthyphenmin and \righthyphenmin parameters instead. Their default values in many document classes are 2 and 3, respectively; put differently, the left-hand and right-hand fragments must contain at least 2 and 3 letters. You could reset them, say as follows,

\lefthyphenmin4
\righthyphenmin4

and recompile the document. Only words containing at least 8 characters will now be hyphenated. The success rate (i.e., the reduction in hyphenation frequency) of this approach will depend crucially on the language in use; if its words are generally short, you'll likely see a huge reduction in hyphenations.