Japanese: http://khcoder.net
English: http://khcoder.net/en
KH Coder is a free software for quantitative content analysis or text mining. It is also utilized for computational linguistics. You can analyze Catalan, Chinese (simplified), Dutch, English, French, German, Italian, Japanese, Korean, Portuguese, Russian, Slovenian and Spanish text with KH Coder.
Screenshots: https://goo.gl/photos/ixn1sTM3jm8o11bP8
Official books (in Japanese): https://amzn.to/3LdRHMJ & http://amzn.to/2wHFxKg
GNU GPL version 2 or later