Before I was able to get this command (Step 5 from Mats’ run.sh), we needed some files that were weren’t aware of. In total, you will need the following files before this command will work. All paths are relative to run.sh.

• data/local/dict/lexicon.txt
• data/local/dict/nonsilence_phones.txt
• data/local/dict/optional_silence.txt
• data/local/dict/silence_phones.txt
• path.sh

prepare_lang.sh will complain if you don’t have any one of these. The complaint for path.sh is a little less clear, since not having this file seems to result in other errors.

lexicon.txt contains a lexical entry on each line which consists of a word, a space, and then the phones in that word, separated by spaces.

nonsilence_phones.txt contains one phone symbol per line.

optional_silence.txt contains the symbol for an optional silence. This is just sil, but the file still needs to exist. Make sure that there is a newline at the end.

silence_phones.txt can be identical to optional_silence.txt

path.sh can be copied from RM, though you may need to edit the KALDI_ROOT variable, since this is a relative path.

The German versions of all of these can be seen in kaldi-master/egs/vm1.

The fstclosure command implements Kleene closure/Kleene star. That is, it converts a set of strings into the set of strings consisting of zero or more repetitions of strings in the input set. The command can also be used to emulate the “+” operator with --closure_plus flag.

For example, given a simple automaton representing the regular expression a(b|c):

========================
Initial automaton
fstprint --osymbols=words.txt --isymbols=words.txt L.fst
0 1 a a
1 2 b b
1 3 c c
2 4 <eps> <eps>
3 4 <eps> <eps>
4

The language a(b|c)

Running fstclosure produces (a(b|c))*:

========================
Run fstclosure for Kleene Star
fstclosure L.fst Lstar.fst
fstprint --osymbols=words.txt --isymbols=words.txt Lstar.fst
5 0 <eps> <eps>
5
0 1 a a
1 2 b b
1 3 c c
2 4 <eps> <eps>
3 4 <eps> <eps>
4 0 <eps> <eps>
4
========================

The language (a(b|c))*

While running fstclosure --closure_plus produces (a(b|c))+.

========================
Run fstclosure for Kleene plus
fstclosure --closure_plus L.fst Lplus.fst
fstprint --osymbols=words.txt --isymbols=words.txt Lplus.fst
0 1 a a
1 2 b b
1 3 c c
2 4 <eps> <eps>
3 4 <eps> <eps>
4 0 <eps> <eps>
4

The language (a(b|c))+