Is Streak localized to my language?
Yes, Streak is available in different languages!
Streak has 20-30 registered languages that goes through Google’s translation engine so all Streak extension material, labels and titles will have translated versions.
After logging in to Streak, open your Gmail Settings and under the General tab you can change your Streak display language.
If you would like to switch to using only Streak in English, you will want to select the Streak menu in the upper right corner of your Gmail and select the link towards the bottom to 'Switch to English'.