Why does "that" sound odd to me after "said" in these sentences with "as" and "like"?
You said that he would come to the party.
He came to the party, as you said that he would.
He came to the party, just as you said that he would.
He came to the party, just like you said that he would.
To me, the word that seems progressively less acceptable in the sentences above. It sounds unobjectionable in the first sentence ("You said that he would come to the party"), but it sounds pretty bad to me in the fourth sentence, and also in the third sentence. I can't decide whether it sounds acceptable in the second sentence. In contrast, all of the sentences sound fine to me when that is omitted: "...as you said he would," "just as you said he would," "...just like you said he would."
Are my acceptability judgements of these sentences shared by others? If so, why is this? I can't figure out why the use of the word like before the clause starting with "you said..." should change the acceptability of the use of that before the clause "he would".
You are reacting to stylistic expectations. That is optional in all four uses. As you add words that can also carry emphasis, it becomes more and more desirable to omit an optional element and thereby reduce the number of words that can be emphasized.
Martin Endley, in Linguistic Perspectives on English Grammar, has a section on optional "that clause complements":
Another striking feature of that clause complements when they function as DOs (direct objects) is that, under certain conditions, the use of the complementizer becomes optional and may be omitted without affecting the grammaticality of the sentence:
(53) a. Dr. Endley knows (that) Ankara gets very cold in the winter.
b. Dr. Endley told his mother (that) Ankara gets very cold in the winter. (p. 372)
What are the conditions of omission? Endley provides three general guidelines that guide usage:
Register. More formal utterances tend to use that, and spoken English is more likely to omit it.
The importance of information in the clause. If the information is more significant, that is more likely to be used. If the information is mostly descriptive, that is less likely to be used.
Distance between the main verb and the that clause. Close proximity renders the that-clause optional; with more intermediate phrases, the need to emphasize the relation to the main verb with a that-headed clause grows.
Guideline 2 is most relevant to your examples. In (1):
- You said that he would come to the party.
The information is stated in full, and so it can be read as relatively significant. That gives an added bit of emphasis. However, in (4):
- He came to the party, just like you said that he would.
"That he would" is the only part of the clause. The that-clause mainly acts to remind readers that you said information similar to the first part of the sentence. Because the information in this clause isn't otherwise significant, it feels odd to emphasize it with that. 2 and 3 follow similar lines: if 2 feels marginally acceptable, it is only because emphasizing that would be less odd without the added emphasis of just before like or as. In other words, at least in 2 that isn't competing for attention.
Source: Endley, Martin J. Linguistic Perspectives on English Grammar: A Guide for EFL Teachers. Information Age Pub., 2010.