I always thought alexithemia wasn't an issue of communication, but one of not being able to identify one's own emotional state. For instance, one of the therapies for my son involved attaching the appropriate emotion to the correct physiological response. He was coding everything as either "happy" or "angry" and was missing out on an entire range of emotion (fear, sadness, anxiety, etc.)
I don't think it was strictly the words, though - it was his responses that were inappropriate. For instance, if he was anxious about school he would lash out angrily...we finally got him to figure out when he's anxious and understanding that made a huge difference.