I think so long as Spear doesn't learn how to speak in any coherent manner, and speaks very rarely, it should be fine. Like, he, his wife and children must have had their own form of names whenever they might've socialized with other whateversapiens. Grunts and stuff are just His language, and learning a few words to help a little with communication is understandable.
Like, if you and other people who didn't speak the same language were stranded on an island, learning one of their languages as a whole would be extremely time consuming, so just you learn their names, and some words to help with communication.
I, for one, really like calling characters by things defining things about them, like Spear, and Fang. I would have liked for, Lilu I think it was, to have just been Crone, or Witch, or something, and to have joined Spear and Fang as a someone with similar trauma as those two, and just trying to live again. Mira even poses the same inherent risk as what some anons used as an excuse for why she couldn't join Spear and Fang and had to die, as "The Coven would have hunted her down". Spear and Fang are gonna save Mira from the slavers, this will rightly piss off the slavers, most possibly making them recurring villains.
On the subject of naming again, I would like it if Mira abandoned her name after she is rescued and just takes up the name of "Bow", when she realizes Fang and Spear's names.