Apparently I have synesthesia, meaning that there's a bit of a mix up between my senses. In my case, it's grapheme -> colour synesthesia, so that letters and numbers trigger colours, as well as ordinal linguistic personification, where numbers, letters, days, and months are associated with personalities, to the point of seeming like people. Numbers are stronger for me than letters - some letters are tricky. N switches from orange to purple depending on the surroundings, and G switches from green to purple. I also have colour -> touch, about which I can find no information except for a brief mention in a list of synesthetic types - but it means that different colours feel different to me, and also skew my perception of the feel of an object. For example, I've been known to pet colour swatches, and they feel like their respective colours, not like the same, shiny material which I know, logically, that they are.

I'd known about synesthesia for a while, but only in terms of sounds -> colours and names -> tastes, not like this. I think that either of those would be a more interesting kind than this, but it's certainly still nice. I looked into it further after a discussion with my mom that started with me commenting on how it was too hot, then acknowledging that it was probably just because of the mustard colour in the room, which felt sticky and warm. That led into the realisation that she didn't feel colours, her random announcement of "five" (she does things like that when she doesn't know what else to say), me saying "is orange, and has nothing to do with this," and her deciding I was insane. Somewhere in there I referred to five as "he" instead of "it," and she thought I was schizophrenic. To prove her wrong, I googled around for colours and numbers and eventually found synesthesia. Since then, I've taken an online battery and scored positively for grapheme -> colour.

Also of interest, it's been discovered that the majority of the population has very mild synesthetic associations. For example, if you are shown two shapes - one pointed all over, like a star, one rounded like an amoeba - and you are asked to name one Kiki and one Bouba, what do you choose? It's amazing how many people agree on it - 95-98%.