"うでどけいをかいます。"

Translation: I will buy a watch.

[azureviolin]

腕時計を買います。

[emzo99]

not accepting "I buy a wristwatch" for some reason.

[V2Blast]

Report it.

[Ever2662]

Same, I've reported it

[XxBiTtEr.S]

What is the difference between tokei and udedokei?

[sirigorn]

All clocks are tokei - wall clocks, digital clocks, watches, etc. Udedokei are only wristwatches. Ude literally means arm, so it's an 'arm clock,' or wristwatch. (Incidentally, 'wristwatch' should be accepted, not just 'watch')

[FrederickEason]

Yes, especially since "watch" could refer to a pocket watch, which 腕時計 cannot refer to, making wristwatch a more accurate translation.

[Kettleman1]

the sentences seem very weirdly structured. Why is it not I will buy a watch?

[IsolaCiao]

That answer is accepted. Japanese doesn't have a future tense, so the -masu form can be translated as the present or future tense.

[Kettleman1]

without the question mark obviously

[mgo904064]

Specifically a wristwatch