Translation:Together we are strong.
By the way this grammar is laid out, the meaning of the Klingon sentence seems to be different from the English sentence. In Klingon, it seems to be saying "We are being strong together", while the English says (more explicitly) "When we are together, we are strong."
Is this a valid assessment? What might be a better Klingon sentence?
It's a very subtle difference that I don't think comes across in the Klingon — that is, I think the Klingon covers both those meanings. You could be more explicit with matay'chugh maHoS If we are together, we are strong or matay'taHvIS maHoS While we are together, we are strong.