The following properties in tr_languages.c control how numbers behave for a
language:
tr->langopts.numbers
tr->langopts.numbers2
These controls how numbers are pronounced.
If numbers is set to 0 (the default value), numbers will not be pronounced.
Setting it to 1 will enable number pronunciation using the dictionary rules.
tr->langopts.max_digits
This is the maximum number of digits that can be spoken by the language. If the number of digits is larger than this, the number is spoken digit by digit.
tr->langopts.break_numbers
This controls how digits are grouped for speaking large numbers. The default is to group into 3 digit groups (thousand, million, billion, trillion, etc.).
tr->langopts.thousands_sep
The character used to separate digit groups. The default is ,.
tr->langopts.decimal_sep
The character used to separate the integer and decimal parts of a real number.
The default is ..