"We only speak a little bit of Japanese."
Translation:Puhumme vain vähän japania.
Place it right before the word you want to connect it to.
Vain me puhumme japania. (It's connected to "we" so it's only us who speak Japanese).
Me puhumme vain japania. (It's connected to "Japanese", so Japanese is the only language we speak.)
Me puhumme vain vähän japania. (It's connected to "a little", so we only speak a bit of Japanese.)