Svet

DB I love so much because I took a training course learning about protactile sign language and found it so incredibly cool how the DB community has been able to make adjustments to sign language overtime and form such an accommodating language yet it's so, so unfortunately rare to acquire, that many DB people use traditional sign language and struggle with distantism (being able to distinguish how far things are in relation to themselves and others) and visualism (visual superiority) because regular sign is still very visual based. Some signs are the same handshape but tapped on different parts of the body so it can be hard to tell apart (those of you who know 'mom' or 'dad' in ASL for example).

Imagine how much more intimate of a bond you'd have with someone that not only knew your native language but also had to communicate it tactilely, not to mention largely unheard of by the general public. A lot of the DB community is quite used to physical contact and try to encourage it because that's the only way they can get information, but for sited hearing people we've created such intense precaution around touch (rightfully so, but-) at the expense of isolating an entire population from society.

I can definitely imagine L being an incredible DeafBlind detective that was born DB and maybe was sent to the Wammy house for this reason where Watari saw his potential and raised him to become prodigious. The Task Force has a hard time navigating the whole thing and understanding etiquette, getting used to the idea that it's okay to make physical contact with someone they don't quite know yet. I can see Light, Deaf or late DB (not born DB), having to overcome his own apprehension toward touch on top of knowingly being Kira. Imagine how L must've felt, feeling Light's touch for the first time and immediately just being able to tell: That's Kira. It's just so characteristic of him.

Light would be so much more conflicted, feeling so insanely attached to the detective and seen yet too seen and knows that he'd have to kill the only person that could ever understand him to such a level of intimacy. I imagine as they use tactile, Light would have passing impulses to just reach out and strangle L, or barely brush certain features like his lips, or find reasons to sign different words to be able to further map each other's bodies more than actually communicating something relevant sometimes.

Here's a very, very brief video explanation of DeafBlind and Protactile ASL where you can see the differences between PT and regular sign language, and why it's so relevant to the community!