1. labs for telecommuniation are usually packed with different equipments from different vendors. NOBODY, at least as I know, is able to handle all of them. Talking to technical support centre is hence unavoidable and happens daily. Your language should be at least good enough to describe the problem. Believe me, it is not an easy job, even if for native speakers.
2. Telecommunication is no more than any other business. To serve its customers, you will need to understand your customer requirements, work with your team to configure the equipments and troubleshoot to ensure the services. To do this, you need to talk.
3. There are senarios when you don't need to talk, i.e., the thing is working fine, business is running as usual. But at that moment, employers don't hire.