Compound words are definitely an example of the kind of language that sends people to the dictionary. In my seventh lesson in the English Writing Skills playlist, I address the complications of punctuating compound nouns and compound modifiers. My basic advice is to consult a trusted dictionary when there’s doubt, and when dictionaries don’t agree, then just choose a pattern and be consistent. For instance, day care will be understood just the same as daycare, but day-care would likely be seen by most as an error.
At the upper levels, students can handle a conversation about how compound words are formed, so I think it’s worth putting words together and taking them apart to discover patterns like those with present and past participles. Through word play (There’s a nice compound! Hm, would you prefer seeing it as one word?) students can also recall familiar compounds like handmade and sunglasses. Do you have tips or patterns to share? Here’s one activity you can try. Please click to view my Something in Common 2_handout.