I use MSWord. If I type "singalong" it flags it as an error, and it suggests "sing along" and "sing-along" as alternatives. It accepts "sing-a-long" if I type it that way, but I think it would do the same with any sequence of 3 valid words connected by hyphens, e.g. "one-two-three" or "one-too-three."

By the way, I once worked in an office where the computer consultant who set up our local network had installed MSWord so that the CUSTOM.DIC file resided on the server, so everyone in the company shared the same dictionary. I can see how that might be useful if you have a careful, literate person managing the file and everyone else keeps their hands off, but that's not what happened.

One day I noticed my spell checker was failing to flag common typing errors, so I investigated, and found that CUSTOM.DIC was full of dozens, if not hundreds, of misspelled words. It looked as if someone in the office (a bad speller or bad typist, no doubt) had been clicking "Add to Dictionary" every time their spell checker found a misspelled word!

I never found out who it was. I cleaned up the dictionary, and checked it periodically after that, and it stayed clean. Evidently the culprit had learned the proper way to use a spell-checker.

The next time we upgraded to a newer version of Word, it was installed in a more conventional way, so that each employee had his own CUSTOM.DIC file on his own C: drive.

I have heard lots of complaints about spell-checkers, but every time I have checked out someone's complaint on my own computer, I find it works just fine.

By the way, I once learned that you can create a file called (if I remember correctly) SUPPRESS.DIC and fill it full of words that you don't like (like "sing-a-long") and MSWord will thereafter always flag those words as errors. That can be very useful, especially if you have to edit documents that other people wrote. I did it once as an experiment and it worked, but that was a couple of computer generations ago, and I don't remember the details.