Screaming is a phase and is common in kids who don't have enough language yet. My son was a late talker, but I didn't give in to the screaming. He also developed a nasty habit of head-bonking - ramming his head into my cheek or shoulder or leg, whatever was closest.
He did a lot of grunting and pointing, which worked to some degree. If I had it to over, I would do sign language.
She keeps doing this because it works. You don't like it, but eventually you give in, right? So that teaches her to yell louder. This is not going to end well.
What I did was take my child away from the situation. Every time. It's annoying as hell, but it's effective. Kids who yell in the park (at kids or adults) get taken out of there, and not with another fun alternative. "We don't yell. If you yell, we leave." Then, at the very next yell, it's into the car with no extra talking. Silence. The consequences have to be immediate at this age. For toddlers, it doesn't work to take away TV or toys later on for an infraction now.
While some things will get easier when she is more verbal, the expectation of immediate results will be well-cemented in her brain if you don't change things up now. My cousins have a 5 year old who has never heard the word "no." Whatever he wanted, he got. He didn't want to go in the car seat at 11 months, so they gave him the iPhone to play with. He didn't want his diaper changed, so they gave him another iPhone (because he broke the first one, of course). He didn't want to sit in a restaurant, but rather than adapt their own pattern (not go out to adult places, get a sitter, etc.), they let him yell (annoying other diners), stack his toy cars on the divided with the next booth (dropping them on unsuspecting diners and then yelling for them to pick up the toys), or walk around freely (causing enough accidents with wait staff that the restaurant told them they couldn't come back even though they had been regulars for years). He's now 5 and very verbal, but they were just at our house for 2 hours and he had 5 tantrums, threw his metal toys or put the full weight of both forearms on the dinner plate, threw cheese back on the appetizer plate because the mom prepped him for not liking it, refused to play with a suitcase of new toys they had brought because I didn't have anything for him to play with (which I used to do but stopped because he never played with them!), demanded entirely different food (and I had made him chicken nuggets and raw veggies anyway), and then pulled his mother's hair and head-butted his father's stomach for a full 15 minutes. He will behave for me if I intervene, and he likes me - but his parents don't like anyone else to calm him down. They hate his behavior, but not enough to exert themselves to actually discipline him with immediate consequences. They find it embarrassing but they think he should just magically outgrow it. Why would he? It works! So, my point is, it's not going to go away by itself. It's not always a language-based phase.
I think it's easier in the long run to undergo the hard stuff now. Yes, redirect when you can. But no, don't wait for it to go away and don't allow repeated screaming to pay off.