What the two underlined phrases refer to?

What the two underlined phrases refer to?

The passage below is from ‘the Blank Slate’ by Steven Pinker.

http://evolbiol.ru/blankslate/blankslate.htm


None of these levels can be replaced by any of the others, but none can be fully understood in isolation from the others.

Chomsky distinguishes all of these from yet another level of analysis (one that he himself has little use for but that other language scholars invoke). The vantage points I just mentioned treat language as an internal, individual entity, such as the knowledge of Canadian English that I possess in my head. But Language can also be understood as an external entity: the “English language” as a whole, with its fifteen-hundred-year history, its countless dialects and hybrids spanning the globe, its half a million words in the Oxford English Dictionary.

In this passage I am not sure what the two underlined phrases refer to.

I have my answers, though.
Can you check them out?

The first underlined 'yet another level of analysis' seems to refer to the content of second next sentence. I mean that it refers to 'language as an external entity.'
(Am I right?)

And 'the vantage points,' to the content of previous sentence, that is, these levels.
(Am I right?)

(I know the passage I quoted lacks context for we have the prescription not to quote more than four sentences. So I hope you can be kind enough to click the link to see more of the context before the posted passage.)

Regards.