Is there any way to increase read speed?
If you mean reading books in the library, there is a workaround, but it requires enabling the console and a little bit of work.
To enable console, make sure the game is not running, then go to the game folder and open renpy/common/00console.rpy with a text editor (notepad will work), and then search for "config.console = False" (without quotes) and change "False" to "True", then save and close the file. This will enable the in-game console by clicking Shift and the letter O simultaneously.
In the console, type: alltime then press Enter, then type: timeday_read, then press Enter. Doing so will display the current value of both variables.
alltime is a variable responsible for overall game time. every minute that passes adds 1 to this value.
timeday_read hovers between 0 and 5, depending on how many times you read any book (in the library). Setting it to 0 resets the counter.
What you need to do is to go to the library and make sure your current time is early enough to read any book five times before the library closes, then check alltime value (say it is equal to X) and memorize this value, then read any book five times, then set timeday_read to 0 and alltime to X, then repeat as desired.
Hint: In the console, you can type several commands in one line by separating each console command with a semicolon, so for example, you could type alltime=X;timeday_read=0 (where X is the value you want).