Are pronouns nouns?

In the Cambridge Grammar of the English Language (Huddleston & Pullum 2002) and many other grammars, the English pronouns are viewed as a subcategory of the English nouns. In other grammars, such as the Comprehensive Grammar of the English Language (Quirk et al. 1985) pronouns are considered a separate category of word, so that we have nouns, pronouns, adjectives, verbs so on and so forth. What are the arguments for including and excluding English pronouns from the English noun category?

Answer

My answer complements this and a previous discussion of the issue

Pronouns: a word class or a subclass of nouns?

by quoting extensively from Aarts' analysis in Modern English Grammar on pages 44-46 under the heading Pronouns (Oxford University Press, 2011).

Pronouns belong to the class of nouns because they can head noun
phrases that function as Subject, Direct Object, and Indirect Object,

Complement of a preposition and Predicative Complement.

Aarts goes on to note:

In some grammars pronouns are regarded as a separate word class. There
are a number of reasons for this. Among them are the following:

• Pronouns show a distinction between nominative, accusative and
  genitive case, while common nouns do not.




• Pronouns show a distinction for person (first person, 2nd person,
  etc.) and gender (he/she, him/her, etc.) but common nouns do not.




• Pronouns do not have inflectional plurals in Standard English (cf.
  *yous, *hes, etc.), although they do have singular vs plural person distinctions (e.g. I vs we). ...




• Pronouns are much more limited than common nouns in their potential
  for taking dependents. For example, while we can have determinatives
  and adjectives in front of common nouns, they cannot generally
  determine and modify pronouns. Thus we cannot say *The he left the
  
  meeting or *Intelligent you did well in the exams. ... Nouns can be
  followed by prepositional phrases as in my cancellation of the
  reservation; pronouns generally cannot.




• Noun phrases with common nouns as Head can have independent reference,
  while pronouns rely on the linguistic or extra-linguistic context for
  their reference. Thus, if I say I met the boss this morning the NP the
  boss refers to a mutually identifiable individual. ... If I say Katie
  married Harry because she loves him then the most likely reading of
  this utterance is for she to refer to Katie and for him to refer to
  Harry.

Despite these observations we take the fact that pronouns can act as
the Heads of phrases that can function as Subject, Direct Object, Predicative Complement, and so
on, as a sufficiently weighty reason for regarding them as nouns.

I think Aarts makes a convincing enough case for pronouns to be regarded as a sub-class of noun rather than a word class in their own right. But I do not expect that this modern analysis will have much impact on pedagogic grammars (as opposed to Aarts' descriptive grammar) or teaching materials.