diff --git a/guide/english/natural-language-processing/index.md b/guide/english/natural-language-processing/index.md
index 3f002664f8..7925e55f05 100644
--- a/guide/english/natural-language-processing/index.md
+++ b/guide/english/natural-language-processing/index.md
@@ -50,3 +50,8 @@ The field of NLP is huge. If you have read this far and have implemented the abo
 * [Natural Language Processing](https://en.wikipedia.org/wiki/Natural_language_processing/)
 * [LSTM networks](http://colah.github.io/posts/2015-08-Understanding-LSTMs/)
 * [Attention](https://distill.pub/2016/augmented-rnns/)
+
+#### Some popular Open Source Tool-kits
+* [CMUSphinx](https://cmusphinx.github.io/)
+* [Kaldi](https://github.com/kaldi-asr/kaldi)
+* [DeepSpeech](https://github.com/mozilla/DeepSpeech)