Select your preferred language by clicking on Edit Profile & Preferences in the upper-right corner of your account.
Scroll to Language and select your preference from the dropdown.
If other members of your group have a different preferred language, the translate icon (shown below) will show up on the post and you can translate the conversation.
Feel free to post/comment in your preferred language as others will be able to translate your post in their account as well.
If you have any questions or need further assistance, please, contact Livingtree at email@example.com.