Language Support

Rasa NLU can be used to understand any language, but some backends are restricted to specific languages.

The tensorflow_embedding pipeline can be used for any language, because it trains custom word embeddings for your domain.

Pre-trained Word Vectors

With the spaCy backend you can now load fastText vectors, which are available for hundreds of languages.

backend supported languages
spacy-sklearn english (en), german (de), spanish (es), portuguese (pt), italian (it), dutch (nl), french (fr)
MITIE english (en)
Jieba-MITIE chinese (zh) *

These languages can be set as part of the Server Configuration.

Adding a new language

We want to make the process of adding new languages as simple as possible to increase the number of supported languages. Nevertheless, to use a language you either need a trained word representation or you need to train that presentation on your own using a large corpus of text data in that language.

These are the steps necessary to add a new language:


spaCy already provides a really good documentation page about Adding languages. This will help you train a tokenizer and vocabulary for a new language in spaCy.

As described in the documentation, you need to register your language using set_lang_class() which will allow Rasa NLU to load and use your new language by passing in your language identifier as the language Server Configuration option.


  1. Get a ~clean language corpus (a Wikipedia dump works) as a set of text files
  2. Build and run MITIE Wordrep Tool on your corpus. This can take several hours/days depending on your dataset and your workstation. You’ll need something like 128GB of RAM for wordrep to run - yes that’s alot: try to extend your swap.
  3. Set the path of your new total_word_feature_extractor.dat as value of the mitie_file parameter in config_mitie.json


Some notes about using the Jieba tokenizer together with MITIE on chinese language data: To use it, you need a proper MITIE feature extractor, e.g. data/total_word_feature_extractor_zh.dat. It should be trained from a Chinese corpus using the MITIE wordrep tools (takes 2-3 days for training).

For training, please build the MITIE Wordrep Tool. Note that Chinese corpus should be tokenized first before feeding into the tool for training. Close-domain corpus that best matches user case works best.

A detailed instruction on how to train the model yourself can be found in A trained model from Chinese Wikipedia Dump and Baidu Baike can be crownpku ‘s blogpost.