Words that make you laugh;)

Whenever a very old man I taught to use a smartphone tells me he'll check/has checked the caravan I can't help giggling. I have a vision in my head of him going outside to check an actual caravan when what he is referring to is the speech bubble that's the symbol for text messages. It has now got to the stage where I will tell him to check the caravan (while giggling) as in his brain it will never be anything else.