Does someone with als lose the ability to speak?

Sadly,: Most (not all) people who are afflicted with ALS will eventually lose the ability to speak, but not necessarily to communicate. There are a number of devices to help with communications. The famous scientist stephen hawkins has one and there are video screens that read a person's eye movements over letters or symbols that will then generate spoken words. Also eye blinking is usually preserved.

You bet: Not uncommonly, the tongue will atrophy, affecting speech articulation, (dysarthria), and progressive ALS eventuates in swallowing, and breathing challenges. So, unfortunately, it does happen.