HCLG

L.fst: The Phonetic Dictionary FST

L maps monophone sequences to words.

The file L.fst is the Finite State Transducer form of the lexicon with phone symbols on the input and word symbols on the output.

L_disambig.fst:The Phonetic Dictionary with Disambiguation Symbols FST

A lexicon with disambiguation symbols

G.fst:The Language Model FST

FSA grammar (can be built from an n-gram grammar).

C.fst:The Context FST

C maps triphone sequences to monophones.

Expands the phones into context-dependent phones.

H.fst:The HMM FST

H maps multiple HMM states (a.k.a. transition-ids in Kaldi-speak) to context-dependent triphones.

Expands out the HMMs. On the right are the context-dependent phones and on the left are the pdf-ids. 

HCLG.fst: final graph

总结一下：

构图过程 G -> L -> C -> H

 G: 作为 acceptor (输入 symbol 与输出相同)，用于对grammar 或者 language model进行编码

 L:Lexicon, 其输出 symbol 是 words, 输入 symbol 是 phones

 C:context-dependency其输出 symbol 是 phones, 其输入 symbol 为表示context-dependencyphones

 H: 包括HMM definitions,其输出 symbol 为context-dependencyphones, 其输入 symbol 为transitions-ids(即 对 pdf-id 和 其它信息编码后的 id)