Typically there is no pluralization in Japanese unless specified. For example:
この車【くるま】は綺麗【きれい】。
This car is clean. / These cars are clean.
Does スポーツ work in the same way? Considering the romanized form of スポーツ is supōtsu (sports), which is plural, does the no-plurals rule work backwards? In this case:
そのスポーツ が好【す】きです！
I like that sport! / I like those sports!
My guess is that it does, but I want to make sure. Thank you!
Japanese usually doesn't distinguish between singular and plural nouns.
スポーツ is thus both singular and plural insofar as the singular/plural distinction even makes sense when talking about Japanese.
There are several other words, which have a ツ at the end, like ドーナツ or ピーナッツ, but only end it a single T. I conjecture that ツ was chosen over ト (as in スポート, ドーナット or ピーナット), precisely because the plural is frequently encountered in English.
In any case, スポーツ can be used when you mean a singular sport, e.g.
クィディッチはハリーポッターの魔法界においての最も人気のあるスポーツである。
Quidditch is the most popular sport in the magic world of Harry Potter.
