1
We need to have a discussion about the project.
To sign this sentence, you would first establish the topic by signing 'project'. Once the context is clear, use the sign for 'discussion' to indicate that a conversation needs to happen. You can use a serious facial expression to show that the discussion is important or necessary.
2
The discussion was very interesting.
Start with the sign for 'discussion' to introduce the subject of your sentence. Then, follow up with the sign for 'interesting' to describe how the conversation went. Be sure to use an engaged, positive facial expression to match the meaning of the word 'interesting'.
3
Let's join the group discussion.
Begin by signing 'group' to indicate that multiple people are involved in the activity. Follow this immediately with the sign for 'discussion' to show the collaborative nature of the talk. You can gesture toward the area where the group is gathering to make the context even clearer.