A linguist friend recently asked me if I thought it grammatical to say ‘Is it a medical hospital or a dental one?’. He wanted to know whether ‘medical’ and ‘dental’ are adjectives in these cases, or parts of compounds, in which case *‘dental one’ would be ungrammatical in the same way that you cannot say ‘Is it a watch maker or a clock one?’
(‘Medical’ and ‘dental’ are interesting because they do not behave like normal adjectives; for example, you cannot use them predicatively: *‘this hospital is medical’.)
I said I found nothing wrong with ‘dental one’. I then asserted that even with nouns, it seemed acceptable, at least in some circumstances: ‘Is it an animal hospital or a people one?’ He was adamant that this is impossible, but it felt OK, if informal, to me.
On the other hand, ‘watch maker or clock one’ definitely seemed totally beyond the pale to both of us, even though the structure is theoretically the same as in ‘animal hospital or people one’.
Somehow ‘watch maker’ feels differently. It is not a type of ‘maker’, it is not just a compound. It feels like more like an inflexional than a derivational process, a fully grammaticalized paraphrase of a verb phrases ‘makes clocks’. ‘Watch’ still feels like a direct object in ‘watch maker’, as if ‘maker’ is closer to being an inflexion of the verb ‘to make’ than to being an independent noun. While ‘hospital’ is indisputably an open-class noun, ‘maker’, which can be compounded with any noun that the verb ‘make’ can take as direct object, feels more like a function word.
In addition, even if ‘people one’ is ungrammatical, it would be understood, and I think speakers often use ungrammatical utterances quite deliberately but for no obvious reason and with no predictable pattern. We could call these ‘as it were’ utterances. E.g. ‘Is it an animal hospital or a people one, as it were?’. Someone I know sometimes describes wooded areas as being ‘very treey’, even though ‘treey’ is not a possible word of English’ due to its phonological bizarreness. The speaker, I am sure, is fully aware that ‘treey’ is not grammatical, you can even tell from the ironic tone of voice such items are uttered in, and these things are not the same as nonce words, which may well obey the grammar of the language and which are generally made out of necessity when no suitable word is available: one could easily say ‘The valley has lots of trees’ or ‘Is this an animal hospital or one for people?’
Of course, people love to play with words and often do all sorts of ‘abnormal’ things in their language, for various purposes, such as talking in a different accent, speaking telegraphically, using Pig Latin etc. However, the ‘as it were’ items do not seem to appear simply when conversation participants are openly using abnormal fun language, or when the things that are referred to by the ‘funny’ phrasings (trees, hospitals), are a subject of fun in the conversation: they appear fairly random. I wonder if they are a strategy of self-deprecation to get put one’s interlocutor at ease by making deliberate ‘mistakes’ and inject a little lightness and humour into an exchange which might not have any in its actual topic. The fact that you can abuse language in this way also shows that you are a creative and lively user of language, so increases your worth in the eyes of interlocutors, whilst the fact that it is random and only on a grammatical level, rather than making clever jokes at the level of meaning, means that it is unthreatening to the other person: using ‘as it were’ utterances makes you sound self-deprecatory and witty at the same time, but not too witty.
Perhaps some of the things I have been rambling about in this post have been investigated properly; if any of you can elucidate any of this stuff more clearly, I would be gratified to hear from you.