The school hired a speech therapist to help the children with their communication skills.

therapist 是由 therapy（治疗）加上后缀 -ist（表示"从事某种职业的人"）构成的名词，指"治疗师、治疗专家"。 speech therapist 指专门帮助改善语言和沟通能力的专业人士，即"言语治疗师"。