Try to imagine how different people could say a thing based on their personality, age, background, how they want people to feel about them. etc.
If I imagine the characters in my comic each telling somebody to wait because they forgot something, it might go something like:
Rekki: "Hey, hold up! You forgot this!"
Rekki always speaks in as short and direct a way as possible, and uses a lot of casual slang. She wants to be liked, and sees herself as a tough gal and an approachable big sister.
Sarin: "Wait a moment. This is yours, right?"
Sarin has the most neutral and academic way of speaking. She speaks with clarity and confidence. She sees herself as a romantic heroine and the person who would be in charge if people had any sense.
Subo: "Ah-! Hey-! You forgot your thing!"
Subo is a gentle guy who doesn't tend to see himself as an authority, so needs to be really pushed before he'll actually use imperative language. He's casual and relaxed.
Jules: "Stop! You might prefer not to lose this."
Jules is a weird mix of a person from a rich family raised to believe they are important and smart (and to be fair, Jules probably does have the highest IQ of the main cast) but also being autistic and uncomfortably aware of people's instinctive discomfort and so quite low self-esteem. So Jules will often give out these very bold, imperious orders... and then follow it up with an unnecessarily long, rambly explanation after the person has done it, that might come off snarky (sometimes intentional, sometimes not).
Try to think about:
Age: My parents are boomers, and so they never say "cool!" or "awesome!", but they do say things like "fab!" A person's vocabulary tends to crystallise a bit around their twenties, so older characters tend to use older slang, and if they do try to use very modern slang, may use it wrong, or use it when it's gone out of style and be "a bit cringe".
Location: A person who grew up in a region with a dialect may have a dialect, but how strong it is can depend on how strongly they want to belong to that community, or how much time they've spent outside of that community. A person's native language and at what age they picked up the second language they're speaking also has an impact on pronunciation, sentence structure and word choice. Even among native English speakers speaking polite English, you'll notice differences in structure and word choice between British, American, Canadian, Autralian, Irish and New Zealanders, even very simple ones like English people will ask about where the "Toilets" or "Facilities" are, while Americans might say "Bathrooms" or "Restrooms" (and in casual English this gets even more fun with British colloquialisms being things like "loos" or "bog" and American ones including "can" and "john").
Be wary that in a comic or novel this can make a character really hard to understand or relate to, or lean into stereotypes, so don't go too far on this one.
Education or Expertise: Getting educated or reading lots of books teaches a person a bunch of useful, more precise words for things. The ability to expand "sadness" into "melancholy", "grief" or "despondence." Then having specific knowledge or expertise in a field will give a person specific, precise words to describe things to do with that field. A person with no expertise sees a sheep and says "That's a sheep", but a seasoned farmer says, "That's a herdwick ewe". Some people have a wide vocabulary, but prefer to use simpler words to fit in, or be easier to understand, others might love showing off the fancy words they know to impress others or seem more authoritative.
Personality: Some people are aggressive and direct, stating what they believe to be true very bluntly and barking out orders, others are more gentle and will try to soften everything with a lot of "maybe", "perhaps", "I think", "just my opinion." etc. Some people are sarcastic and passive-aggressive, often getting across the feeling of somebody who is used to not getting what they ask for, or having their suggestions or orders ignored.
So if you add all of these together, you might get:
"Mate, wipe yer grubby boots before you come in here!"
-Direct, casual, maybe British/Aussie. Might be a tough working class guy from London.
"Dude! Wipe your kicks, man! You're making a mess of my house!"
- Comes across like a casual, younger American. It's direct, but in a more pleading, less aggressive way than the one above.
"Excuse me, but could you maybe wipe your shoes before you come in? Thanks ever so much."
- Indirect, polite, but not formal, American. Might be a fussy, slightly old-fashioned older lady from Texas.
"Sir. You are strongly encouraged to remove the dirt from your shoes before entering this residence."
-Formal and polite, but quite direct. This sounds like a fussy butler who is being polite, but kinda thinks he's the one in charge on some level.
"Oh don't mind me, just tramp mud all over my place!"
- Passive-aggressive and sarcastic, casual. This person is angry, but kind of indirect. They probably are used to not having a lot of power to get people to do what they want, and vent their frustration by complaining.