I wish I could sleep 10 hours a day.
Well... if it is not under control, it's called narcolepsy, therefore someone with such disorder may be called narcoleptic.
[I am not a teacher]

Other
Hello,
I'm looking for a word that English speakers use to describe a person who likes to sleep a lot and often oversleeps. I've looked up 'lazybones', but the entry says it refers to a lazy person. 'Sleepyhead' doesn't work either.
I'd ve very grateful for help.
Thank you.
I wish I could sleep 10 hours a day.
Well... if it is not under control, it's called narcolepsy, therefore someone with such disorder may be called narcoleptic.
[I am not a teacher]
Thanks, but it sounds somewhat technical to me. I'm looking for a colloquial term... I'm sure there should be one.
Hi Verona.
I'm wondering why "sleepyhead" doesn't work for the context you have. It is exactly what you would call someone as you shake their shoulder or call into their bedroom to wake them, or poke them in the back when they doze off at their desk – "C'mon sleepyhead, wake up!".
There are words that describe a sleepy demeanor, dozy, drowsy etc, but they don't necessarily suggest that the person sleeps a lot, just that they appear sleepy.
not a teacher
Sleepyhead is correct for this context.
Not a teacher
I rejected it at first because I read that
"sleepyhead = used for referring to someone, especially a child, when they have been sleeping and have started to wake up".
The context that I want to use the word in is as follows:
"Where's Paul? - He must have overslept again. Everybody knows he's a [sleepyhead], so he's often late".
"Where's Paul? - He must have overslept again. Everybody knows he's a [sleepyhead], so he's often late".
Verona.
– "sleepyhead" is often used when referring to children and this does carry over when you're talking about adults, it almost has an endearing tone rather than being harshly critical. "Don't expect my brother to be there so early, he's a bit of a sleepyhead".
For the context you give, other possibilities are:
"Where's Paul? – he must have overslept again. Everybody knows he loves his sleep, so he's often late".
"... knows he's a heavy sleeper .."
"... knows he sleeps like a log .."
.. and so on.