Obviously, all DCs and reasons for speech delay are different but I think it can be helpful to share experiences as something useful might be picked out of it.
My then 2, (nearly 3) yo was speech delayed and I was very worried. He was delightful but seemed a bit blank sometimes and he just didn't chat or have many words. He did a lot of something called "echolalia", so I'd say "Would you like a drink?" and he'd say "Want drink?" as a question back to me. Or I'd say "Look, it's a big truck!" and he'd say "Big truck?" as a question. He didn't have much unique input.
I took him to two SLTs. The first was terrible, she hadn't come prepared with the right speech tests for his age group and so tested him against what she did have (3-6, when he wasn't even 3 then), needless to say he tried but failed on most of that and it made me feel worse. I didn't continue with her, obviously.
I then took him to a really good, very qualified SLT. She carefully and gently tested and analysed his speech and concluded that (in his case) he was missing a lot of verbs ie "doing" words and to focus on those so he could structure longer sentences instead of single or two words, but ultimately he would be fine (she was right). She said in his case the echolalia was because he wanted to contribute to the conversation, and he did recognise the turn-taking pattern of verbal communication, but didn't have the vocabulary to form an individual response.
The My Toddler Talks book really helped me to find ways to build on those verbs or "doing" words, so when he would say (for example) "Blocks", I'd say "That's right! We are playing with the blocks!" (or whatever) and/or "Shall we stack the blocks up? Let's stack the blocks. You are stacking the blocks!" (whilst showing him stacking). Or, he'd say Puddle and I'd say "That's right, it's a puddle! We are splashing in the puddle!" (modelling splashing). He'd say "Cup", I'd say "Yes! You are drinking milk from your cup! Shall I drink from my cup too? I am drinking from my cup!" (whilst modelling drinking). It was all about taking what they said, no matter how little, and building on it.
Also I found it reassuring to know that even an "Um" response or any kind of verbal response at all, to start with, even if it's a noise rather than a word, is still a form of verbal communication. So you might say "Can you pass me the teddy bear?" and they say "Bemf" and you say (slowly and clearly) "That's right! It's the bear! You are passing me the bear! Shall I pass you the bear? I am passing you the bear!" (modelling passing back and forth whilst also clearly enunciating the word Bear). The book recommended things like having a basic doll's house (I bought a Fisher Price one so it was toddler-friendly) so everyday activities and actions and rooms could be identified. The same with a baby doll, modelling bathing, washing, drying, sitting and words like towel, soap, hair, face, nose, eyes, fingers etc. You basically provide a running commentary using as many useful words as possible rather than just 'Thank you, that's clever!" or whatever. Say what you see all the time! As for the nouns, even if she says "tee-tor" for tractor, just say "That's right! It's a TRACTOR!" and repeat it slowly and clearly to her as many times as you can in sentences, with a relevant verb ideally.
My DS is now 8 yo, is fluent, is definitely NT (the thought had crossed my mind he might not be back at age nearly 3) and doing well in school. He's just naturally a quiet not a chatterbox type, that's just his personality, compared to his elder sister who is a chatterbox! So hang in there, take the advice of your SLT first and foremost, but in my case practicing "saying what you see" to model not only nouns but verbs too was helpful and the book was full of useful ideas too. Let us know how you get on x