This is a very interesting question. Being from California, I was always curious about the linguistic diversity of the indigenous population in California prior to colonization. However, I think you’ll get a more thorough and accurate answer from r/AskAnthropology or r/Linguistics.

How accurate is the map in the first place? Where did the author of the map get the info from? Were Spanish explorers documenting languages the same way as French or English explorers? Ie, is the baseline the same? How homogenous are the largest groups and how similar were the smaller groups?