Is the word language in this context a proper noun?

My phrase is "Spanish language TV spend" with respect to advertising on Spanish language TV ads.

In this context, should the l in language be capitalized?

Following John Lawler's recommendation (in the comments above) to hyphenate "Spanish-language" would help readers grasp the intended meaning of the rather disjointed, noun-heavy string of words "Spanish language TV spend." Adding the hyphen might also weaken your impulse to (needlessly) capitalize language, since it tightens the visual connection of Spanish to language and emphasizes the subordinate relationship of Spanish to language.

So on the positive side, adding a hyphen improves the phrase's coherence. On the negative side, adding it introduces a little black line segment to the text—which many advertisers seem to dislike. The only explanation I've gotten from ad sales people who oppose this kind of clarifying hyphen is that hyphens "clog up" the wording and make it look "less open and inviting to readers." I don't find that to be true at all, but I suspect that an institutional prejudice against punctuation—even quite useful punctuation—lies behind some problematic open constructions that appear in ads.

Paradoxically the visually open, punctuation-free wording may tend to slow readers down as they try to figure out what word goes with what other word—and advertisers tend to like it when readers slow down while reading their ads. This, at any rate, is one possible explanation for the frequent absence of hyphens from ads in places where they would be helpful.