I know that conventionally thy is used before consonant noun while thine is used before vowel noun, however I wonder is this a legal grammatical rule or just a mere convention.

Example, can I say "thine vanity" instead of "thy vanity" or "thy afflictions" instead of "thine afflictions"
Hello, avid learner - and welcome to English Forums.

First let me make it very clear that you cannot say any of those because neither word is used in contemporary English. These 2nd person singular familiar pronouns/adjectives were superseded by 'you' in the late 1600s. They lingered amongst the Quakers (a Christian sect) until almost 1900.

However, that was the rule.
avid learnerExample, can I say "thine vanity" instead of "thy vanity" or "thy afflictions" instead of "thine afflictions"
Not if you are following the example of Shakespeare.

thine afflictions (c.f. an affliction)

thy vanity (c.f. a vanity)

Of course, you'll sound like a total nutcase if you actually say these things in an ordinary English conversation.


Your idea of a "legal grammatical rule" is puzzling. Do you think you'll end up in jail if you don't follow the Shakespearian convention?

What is a grammatical rule if not a convention?

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Well, the word “legal”, is probably a bad wording.

What I mean by “legal” is really “standard”.

Standard grammatical rules are mostly written, formal, and codified; so they have a strict concept of right and wrong or permitted and unpermitted.

Example: “I are a accountant” is definitely wrong. The right auxiliary verb in this example is of-course “am” and the article is “an”.

Conventions are usually unwritten, informal, and uncodified; so they have a loose concept of permitted and unpermitted.

Example: “Bears will hibernate in winter.” The article “the” before the noun “winter” conventionally can be omitted.

Anyhow, thank all of you for your answers.