Should I use a comma with a phrase and clause modifying the same noun?

Question

There were things strewn on the floor which the child could have put in his mouth.

Should I use a comma here? Without one, it looks like it's saying the child could have put the floor in its mouth.

Answer 1

There is no need for a comma. "strewn on the floor" is describing the "things" so it can be inferred with common sense that the floor is not in someone's mouth. This could be formed into an appositive phrase if you need to do so, which requires commas. eg. There were things, (appositive phrase), which the child ....

Answer 2

A similar sentence not so easily disambiguated by common sense is

• There were large boxes on the rickety table which the child could have pulled over onto himself.

This type of sentence is very common in spoken English; here, the disambiguating rewrites would probably be less usual than the sentence as written. However, disambiguation would be effected by intonation in spoken English:

• There were large boxes on the rickety table which the child could have pulled over onto himself.

• "There were things strewn on the floor which the child could have put in his mouth."

[I'm using italics to show destressing here; as this is non-conventional, this device can't be used without this caveat, which is of course unwieldy.]

Commas are likewise no help here; one is left with the original to represent the quote.

Answer 3

There were things strewn on the floor which the child could have put in his mouth.

Your example is simply poor English - with or without a comma. It should read:

There were things, which the child could have put in his mouth, strewn on the floor.

or

There were things that the child could have put in his mouth strewn on the floor.

or

Strewn on the floor were things that the child could have put in his mouth.

Where you see ambiguity, please consider correcting it.