Breakdown of Tämäkään harrastus ei ole halpa.
tämä
this
olla
to be
halpa
cheap
ei
no / not (en, et, ei, emme, ette, eivät)
Questions & Answers about Tämäkään harrastus ei ole halpa.
Why does the ending -kään attach to tämä instead of the verb?
The ending -kaan/-kään means "either" or "neither" in a negative sentence, and it attaches directly to the word being emphasized. The speaker is comparing hobbies, saying "this hobby isn't cheap either", so the ending goes on the word tämä (this).
Why is the ending spelled -kään here rather than -kaan?
It comes down to vowel harmony. The word tämä contains the front vowel ä. Therefore, it takes the front-vowel version of the ending, which is -kään. If the word had back vowels like a, o, or u, you would use -kaan.
If tämä and harrastus belong together, why doesn't harrastus also get the -kään ending?
When a phrase consists of a pronoun or adjective plus a noun, the clitic -kaan/-kään only attaches to the very first word. Adding it to tämä is enough to apply "either" to the whole phrase tämä harrastus (this hobby).
I often see partitive case used in negative sentences. Why is halpa in its basic nominative form here?
It is true that negative sentences often trigger the partitive case for objects. However, this sentence does not have an object; it is an "A is B" type sentence. In negative sentences of this type, the adjective describing the subject stays in the basic nominative case, just like it would in a positive sentence.