Original: During the episode, Rachel demonstrates many signs from a certain topic (schools, daytime activities, etc.) and then has Leah and Alex sign - although they now sign first - alongside with a montage of many other children of different backgrounds.
Simplified: During the episode, Rachel shows many signs from a certain topic (schools, daytime activities, etc.) and then has Leah and Alex sign - they sign first now - alongside with many other children of different backgrounds.