Confusing syntax in sentences with indirect object complements

Question

Some verbs produce unambiguous syntax when used with an indirect object.

    I brought a toy to Katy. --> I brought Katy a toy.

    I bought flowers for my wife. --> I bought my wife flowers.

Neither of these sentence complements can be interpreted as a single noun phrase or object complement.

But if we use a pronoun instead of a proper noun we sometimes produce ambiguous syntax.

    I brought a toy to her. --> I brought her a toy.

    I bought flowers for her. --> I bought her flowers.

The first sentence is not ambiguous because her a toy is not a sensible phrase, but her flowers is easily interpreted as a noun phrase (poss dt + n) that functions as the single direct object of the verb. Two possible interpretations with very different meanings.

Furthermore, BBC Learn English lists keep as a verb that can be used with OCi/OCd syntax but I can't seem to find a sentence that isn't ambiguous.

1. I kept the money for you. --> I kept you the money.
2. I keep the keys for the manager. --> *I keep the manager the keys.
3. I keep secrets for her. --> I keep her secrets.
4. I keep secrets for Jill --> *I keep Jill secrets.

Sentences 2 & 4 produce nonsense, and sentence 3 produces ambiguous syntax, where the OCi and OCd merge into a single noun phrase. Sentence 1 seems to work but it feels very awkward to me. But all of these sentences follow the rule of having a beneficiary or recipient of the action using to or for adverbial complement in the standard form.

So what's going on here? Does keep belong on this list or not?

Answer 1

It belongs in the list in the sense that it's a "double object verb", but not in the sense that it doesn't fit the article's "V + N (indirect object) + N (direct object)" convention.

I think "V + N (indirect object) + N (direct object)" is a simplification of a third, unmentioned rule: "V + , + Prepositional phrase (indirect object) + , + N (direct object)". However, this simplification doesn't work for the verb "to keep" in formal English hence the confusion.

To demonstrate, reconsider your examples with these rules using the format (1) → (2) → (3):

1. V + N (direct object) + Prepositional phrase (indirect object)
2. V + , + Prepositional phrase (indirect object) + , + N (direct object)
3. V + N (indirect object) + N (direct object)

I brought a toy to Katy. → I brought, to Katy, a toy. → I bought Katy a toy.

I bought flowers for my wife. → I bought, for my wife, flowers. → I bought my wife flowers.

I brought a toy to her. → I brought, to her, a toy. → I brought her a toy.

I bought flowers for her. → I bought, for her, flowers. → I bought her flowers.

I kept the money for you. → I kept, for you, the money. → I kept you the money. (colloquial)

I keep the keys for the manager. → I keep, for the manager, the keys.

I keep secrets for her. → I keep, for her, secrets.

I keep secrets for Jill → I keep, for Jill, secrets.

Secondly, your example "I keep her secrets." doesn't fit format (3); in this case, the direct object has changed from "secrets" to "her secrets", and there is no indirect object. As a consequence, there's no ambiguity.

Another example might be helpful:

I keep a secret for her. ≠ I keep her a secret.

In this case, misapplying rule (3) dramatically changes the direct object from "a secret" to "her" and, therefore, completely changes the meaning of the sentence.