Telephone interpreting is when there is someone who speaks a different language than you and you need to talk to them. You pick up the phone and call a special person called an interpreter. The interpreter understands both languages and can help you talk to the other person. They listen to what one person says and then tell the other person what was said in a language they understand. It's like having a translator on the phone!
For example, if you needed to talk to someone who speaks Spanish but you only speak English, you would call an interpreter. You would tell the interpreter what you want to say and then they would tell the other person in Spanish. When the other person talks in Spanish, the interpreter tells you what they said in English. This helps people who speak different languages understand each other and talk to each other over the phone.