Related to this question: Nasal /i/ in French exists?
I noticed at times, the phoneme /i:/ in French is pronounced with more "constriction", like it happens in Swedish (https://youtu.be/wIlOPJLhks4?t=37 at 0:37 on "latin")
Same as Juan in the related question, I also thought at first that it was due to some kind of interaction with the preceding phoneme, but I came across a sample of a native speaker doing this on the word "si" with the vowel somewhat elongated: https://www.youtube.com/live/OWp1LZNU7k0?t=911 (at 15:11)
It's especially clear when you compare it to something like the Spanish "sí" or "si"
Here is another example given by Juan, along with his thoughts
Here's a link to a video of a female French native speaker: https://www.youtube.com/watch?v=5-_EZDKFv7U
I think she realizes that same phoneme when uttering certain words such as "aujourd'hui" (0:37 in the video)--which could be some sort of a diphthong pattern where /i:/ is somehow affected by the preceding phoneme /ɥ/--and then again at 1:02 when she says "traduire" (same mechanics involved as the example above).
I definitely hear more constriction in the realization of that /i:/. It may only occur in the phonetic diphthong pattern /ɥi/ that is phonemically realized as /ɥɪ̝ʝ/ (if that even exists, of course); I don't have any other examples at the moment, but I'll share them with you in case I come across any in the future.
Is this part of a dialectal variation? Where can I find more information about this?
I couldn't find any sources regarding this, but I'm not sure what I would even search for.
Edit: additional example: https://youtu.be/A_EkF94Zg0k?t=173 (Ici, cabinet, Tel-Aviv)