"other factors" can be treated as a singular group noun if you want, so I think both are correct.

By example:

"There are likely to be cows over that hill" - correct, many cows

"There is likely to be a herd of cows over that hill" - correct, one herd

"There are likely to be other factors" - correct, many factors

"There is likely to be a number of other factors" - correct, one collection of many factors

"There are likely to be a number of other factors" - correct, emphasizes the factors over the collection

"There are likely to be other factors" - correct if you want to treat 'other factors' as a singular group. Up for debate.

Also, "there're" is very hard to say, so using "there's" as a contraction for "there are" is, in my book, okay, even if it's not technically correct.

I agree with all of your examples. But his sentence misses the crucial to be part to be correct. I'm just wondering whether this is deliberate and just a way of speaking informal english, or just the person doesn't know it's incorrect

I'm a native English speaker, and if I'd spoken what they said out loud then I would've said "there's" precisely because "there're" is more difficult to pronounce. It's also how I'd write it, even though I know "there is" is not correct; it's just an evolution of the language, like "ain't".

It's a common way of speaking informal English.

Its written the way it'd be spoken, which seems fine for informal writing

Yep. The thoughts are evolving during the speech process. The speaker might start the sentence thinking about one factor, but decides to make it plural after the first words have already started.

I don't think this is the case.

1. If you accidentally say There is and want to use a plural after, (for example, a lot), you can just say a number in between. The sentence stays correct, you just have to say 2 additional words. I personally never had this problem

2. This is internet. You are free to edit your comment and reread it a million times before posting

Hope you understand what I'm trying to say, not being native sometimes restricts my ability to properly articulate semi-complex stuff

These are all things people can do, but might not be in the natural flow. Any it depends how the person is speaking. To use a car analogy, a driver can either be looking far ahead and flowing smoothly or looking only a short distance ahead and having to make lots of awkward adjustments. I personally go back and edit things most of the time, but that takes more time for only "style points" in most cases.

You have very strong opinions about correct English for someone who doesn't speak it as a native language.

Those are not opinions, I am handing you literal facts

hell, I'd argue that it should be fine for formal writing as well. Ideally, the gap between written and spoken language is as narrow as possible, since ideally a written text communicates with the reader directly, with as little hurdles to parsing the content as possible. Having to maintain a secondary vocabulary is exhausting and creates barriers. There is a limit to how permissive I am with this personally though, generally I'd only be happy with changes that are semantically near identical, or introduce words which represent genuinely novel concepts rather than slang that re-brands existing concepts.

The point is it shouldn't be spoken like this. It's just wrong. I'm wondering whether the person is unaware or is this some slang I don't know about. I've seen a bunch of people speak like this, I'm trying to understand the reason

> It's just wrong.

Language is ultimately descriptive, not prescriptive -- so common patterns are never "just wrong". But as someone who taught English for many years, I'm actually fascinated by what you've noticed. Because as an overeducated native English speaker, I observe that:

- "There's likely other factors" sounds totally fine to me.

- "There is likely other factors" sounds horribly wrong.

- "There's other factors" sounds wrong, but not horribly so.

- "There are likely other factors" sounds fine, but you wouldn't usually say "there are" as two distinct words, you'd say...

- "There're likely other factors" which would sound fine if perfectly enunciated, except the "'re" tends to get swallowed up and it will easily sound like "There likely other factors" to the listener which will sound wrong

So my theory here is that, in order to aural eliminate confusion between "there" and "there're", there's an unwritten rule in spoken English where we substitute "there's" instead when the plural object isn't immediately following, but has an adverb intervening.

I'm not 100% sure this is a full explanation of the phenomenon, but what I can tell you is that criticizing it is useless. It's just how native speakers talk -- it's conventional English (at least in the US). What is interesting is investigating it, though! So thanks for noticing a little quirk of English like that.

According to whom?

Why are we grammar policing on hackernews? This is a tech and startup forum not a language forum.

That’s a natural way to speak in American English anyway. You wouldn’t say “there is”. But “there’s” is fine.

It's not about the contraction of there is, there are has a completely different meaning

If something is used often to mean X - it starts to mean X. That's how language works.