firstly , as @lissyx said, you must ensure your ds version and and ds_ctcdecoder are same, and then ,if you add some new alphbet into alphabet.txt , you must have to rebuild wors.arpa 、lm.binary with kenlm tool ,and then use the generate_trie to generate trie binary , finally update the train shell (the path of the files you have updated). following is my environment:
(deepspeech-venv) (base) zhangp@zhangp:~/tmp/deepspeech-venv$ pip list
Package Version
absl-py 0.9.0
astor 0.8.1
attrdict 2.0.1
audioread 2.1.8
beautifulsoup4 4.8.2
bs4 0.0.1
certifi 2019.11.28
cffi 1.14.0
chardet 3.0.4
decorator 4.4.2
deepspeech-gpu 0.6.1
ds-ctcdecoder 0.6.1
gast 0.2.2
google-pasta 0.1.8
grpcio 1.27.2
h5py 2.10.0
idna 2.9
joblib 0.14.1
Keras-Applications 1.0.8
Keras-Preprocessing 1.1.0
librosa 0.7.2
llvmlite 0.31.0
Markdown 3.2.1
mock 4.0.2
numba 0.48.0
numpy 1.18.1
opt-einsum 3.1.0
pandas 1.0.1
pip 20.0.2
pkg-resources 0.0.0
progressbar2 3.47.0
protobuf 3.11.3
pycparser 2.19
python-dateutil 2.8.1
python-utils 2.3.0
pytz 2019.3
pyxdg 0.26
requests 2.23.0
resampy 0.2.2
scikit-learn 0.22.2
scipy 1.4.1
semver 2.9.1
setuptools 45.2.0
six 1.14.0
SoundFile 0.10.3.post1
soupsieve 2.0
sox 1.3.7
tensorboard 1.15.0
tensorflow-estimator 1.15.1
tensorflow-gpu 1.15.0
termcolor 1.1.0
urllib3 1.25.8
webrtcvad 2.0.10
Werkzeug 1.0.0
wheel 0.34.2
wrapt 1.12.0