The therapist helped them talk through their long-standing communication issues, which was crucial for reconciliation.

talk 的意思是"谈话、交谈"，这里指通过对话来解决问题。 through 在这里表示"彻底地、完整地"，强调讨论的全面性和深入性。 talk through 这个短语的意思是"详细讨论、彻底沟通"，指通过充分交谈来解决问题或达成共识。