Multinyms, so words with multiple pronounciations/names?
Anyway, I'm not a native speaker, but e.g. air, are, e'er, ere, err, heir does not sound identical to me. The Oxford English Dictionary says: ɛː, ɑː/ə, ɛː, ɛː, əː, ɛː, which makes are and err different. Unfortunately, the author doesn't give a source, so it's probably just his dialect?
Anyway, I'm not a native speaker, but e.g. air, are, e'er, ere, err, heir does not sound identical to me. The Oxford English Dictionary says: ɛː, ɑː/ə, ɛː, ɛː, əː, ɛː, which makes are and err different. Unfortunately, the author doesn't give a source, so it's probably just his dialect?