The Phisics, Music, Science Fiction etc sites have different icons. Why doesn't this one have one too? And is there any prerequisite to a site that may prevent this one to have an icon?
Linguistics SE was in beta until very recently. (Congratulations to our 29 oldest beta sites - They're now no longer beta!) We are out of beta now, but only in name. We have none of the features of mature SE sites.
Going by the phases in Design-Independent Graduation is on for early September! Linguistics SE has only gained the first bullet point of Phase 1. For all practical purposes, just assume we're still in beta here.