Customised GPTs for Lexicography

About a year and a half ago, lexicographers realised that the enthusiasm they had when using ChatGPT-3.5 for English lexicography, could not be carried over to other languages, not even big ones like Portuguese. A year ago, the lexicographic community was made aware that ChatGPT-3.5 could not be used at all for small languages, and especially not for oral ones like Lusoga. In mid-2025, we notice that the models have improved drastically. Both Gemini-2.5 and especially GPT-4o perform miracles on languages like Portuguese, and for undocumented languages like Lusoga, customising GPT-4o by feeding it corpora as well as entire dictionaries is a major step forward, down to tackling neologisms. We are not yet there in full but moving forward.