I've been collecting some simple tips over the years to make distinct voices when one doesn't pop up immediately. Though for good dialogue, I'd start focus in character motivations and negative experiences/traumas as those will guide what they want to talk about in any given situation, which is more important for characterization than a clear voice. If you don't know why a character says what they say, it hardly matters how uniquely their message is worded.
But here. This list is made so that ESL and people who can't 'feel' accents as easily can make unique voices too. Personally I'm ESL so can't remember various English accents if someone had a gun to my head.
Character voices
You need various voices. A wide palette of colors of voices to make reading dialogue more interesting. Combine 1-3 of these traits with fun contrasts in mind to create unique character voices.
Profession language/slang: A character is a mechanic, scientist, etc. and gets words and metaphors flavored from their occupation or background.
How aggressive/submissive they are in conversation: Do they initiate difficult conversations with people they hate or, or do they tend to dread the question and tip-toe around it whilst careful not to offend anyone? (depends who they're talking to ofc)
Amount of humor they use. How much they use humor or like to keep conversations light. Do they make a joke of everything?
Uncertainty: Do they frame everything as a question?
Hesitations and Pauses: Frequent use of fillers like "um," "uh," "you know," or significant pauses in their speech could indicate uncertainty, thoughtfulness, or a tendency to speak before thinking.
Wishywashy/longwinded-vs-straightforward. How easily they get to the meat of the business vs how much fluff they like to use in talking about inconsequential stuff that please them.
Terse: Short sentences.
Tenses: Speaker uses a tense that's a little bit off, like "always uses 'shall' instead of 'will'", or uses past tense instead of past perfect, or never uses imperfect tenses. Maybe always speaks in present tense?
Conjugation: Character might conjugate all verbs in the third-person. They says this and watches that and likes the schemings and plottings. Or they might not conjugate verbs at all. Speak like Grog Gorilla who go walk in park! Usually used by some kinda animal or foreigner.
Avoids possessive pronouns: "he has a thoughtful expression" instead of "his expression was thoughtful". This kind of phrasing works better than "the expression of him was thoughtful", which is unwieldy.
Replace pronouns with names or nicknames.
Nicknames for everyone!
Endearments: hun, baby, etc.
Expressive Sounds: Non-verbal sounds like sighs, laughs, grunts, or groans as part of their communication style.
Breathless: Insufficient or no punctuation. Just doesn’t give a flip speaking without punctuating or pause no matter what speaking so even if it made no grammatic sense.
Brevity: Leaves out normal words if they're not needed for clarity: "Went to store" instead of "I went to the store". Or even "Store."
Shatner: Pauses mid-sentence. For emphasis.
Articles for emphasis: Uses "the" instead of "a", to call attention to a noun. "He bought the beautiful rug" even though "rug" had not been mentioned earlier.
Favorite word: uses a common word more often normal, or in not-quite-appropriate ways. Modern use of "like" for emphasis, for example. Patrick O'Brien had characters use "which" in this fashion. 'And he asked a third time, which he's not gonna like the answer, you mind me.' A "favorite word" doesn't have to be grammatically correct by normal English rules but whatever meaning or purpose they serve for the character, it should do so consistently.
Formal: Elegant, grammatically-correct sentences.
No contractions: Goes well with formal. Also can be ESL.
Casual: Chatty, uses sentence fragments, uses filler words, lots of contractions, colloquialisms.
Erudite: Uses big words. Also goes well with formal.
Plain-spoken: Uses small words
Bless your heart: Avoids hostile/angry language. Patronizingly kind when annoyed, if not deliberately using kind-sounding phrasing while meaning the opposite.
Negativity: Frames things using negative language, in terms of no/not/un-/in-/won't/don't. Eg, might answer "How are you today?" with "nothing's gone wrong so far" instead of "fine". This doesn't necessarily mean the character is negative or unpleasant. For instance, "no problem" is the negative-language version of "you're welcome." Tends to come across as blunt or a downer, however.
Positivity: Avoids using negative language. Eg, instead of saying "No" to an invitation, explains that they have a prior commitment. Doesn’t have to be a bubbly chipper character though. Positivity can come from a deadpan character as great irony.
Rising tone: When uncertain, ends statements with a rising tone (question mark) even if they aren't phrased as questions.
Flat tone: Makes statements out of things that are phrased like questions.
Brusque: Leaves out normal courtesies, like hello/please/thank you/you're welcome/goodbye
Alternate courtesies: eg, "you have my thanks" instead of "thank you" or "no problem" or "my pleasure" instead of "you're welcome".
Polite: uses courtesies frequently. Or uses elaborate ones, or to excess. "A great and wide apology, noble sir, from this humble servant."
New colloquialisms: turns of phrase appropriate to the setting/character religion (or dominant religion: characters may swear by a god they don't believe in)
Multilingual Elements: Incorporating words or phrases from other languages they know, which can be used to express certain feelings or thoughts more precisely.
Idiosyncratic Grammar: Unique grammatical quirks that aren’t standard but consistent for the character, like always using double negatives or never using conjunctions.
Swears like a: Uses frequent inventive imprecations. Or uses curse words casually/constantly
Code-switching: Changes speech patterns depending on who they are with (most people do this to one degree or another, but it is more or less marked depending one circumstances.)
Echoing or Mirroring: A character who often repeats or mirrors the speech patterns and phrases of others, which could indicate a desire for approval or a lack of confidence in their own voice.
Respectful: Addresses people by title & surname.
Rude: Avoids calling people by name, may not know names. "Hey, you."
Poetic: Likes using alliteration and/or rhymes and/or particular rhythms in their speech.
Speech Speed: Some characters might speak unusually fast or slow, which can reflect their personality or emotional state.
Volume and Tone Variations: Some characters could be known for their soft-spoken nature, while others might have a booming voice. Their tone might vary from gentle and soothing to harsh and grating.
Metaphorical Language: Some characters might frequently use metaphors and similes, indicating a poetic or abstract way of thinking.
Historical or Cultural References: Some characters might frequently reference historical events, cultural artefacts, or popular culture, indicating their interests or background.
Voice Quality: Describing the character’s voice in terms of its quality - raspy, smooth, nasal, deep, high-pitched.
Repetition for Emphasis: Some characters might have a habit of repeating words or phrases for emphasis or due to a nervous tic.
Selective Mutism: A character who chooses not to speak in certain situations or to certain people, which can be powerful in showing their emotional or psychological state.
Storytelling Flair: Some characters might have a knack for telling stories or anecdotes, often going on tangents with rich detail or dramatic flair.
Interrupting or Overlapping: Characters who frequently interrupt others or talk over them can indicate impatience, dominance, or lack of social awareness.
Use of Silence: A character who strategically uses silence or non-response in conversation, which can be as telling as what is spoken.
Personal Catchphrases: Unique phrases or words that a character frequently uses, contributing to their signature style.
Intonation Patterns: The musicality of the voice, where some characters may have a sing-song way of speaking, while others may have a more monotone delivery.
Mannerism & Presence
Another quick guide (This part is not finished)
Childlike sway.
Someone light on their feet.
Someone uncoordinated.
Cautious, as if they gonna break everything.
Confident Stance: Standing tall, shoulders back, exuding self-assurance.
Fidgety or Nervous: Unable to stand still, constantly moving hands or feet, or shifting weight from one foot to another.
Relaxed and Casual: Leaning against a wall or object, hands in pockets, exhibiting a laid-back attitude.
Intense Focus: Staring intently at something or someone, almost as if they're lost in thought or in a trance.
Defensive Posture: Arms crossed, possibly a slightly hunched posture, indicating defensiveness or discomfort.
Elegant Poise: Standing with refined grace, perhaps with one hand lightly resting on a hip, chin slightly raised.
Tense and Uptight: Rigid posture, hands clenched or gripping something tightly, showing stress or anxiety.
Imposing Dominance: Taking up space, perhaps with hands on hips and feet apart, exhibiting control or authority.
Distracted and Disengaged: Looking around frequently, not focusing on anything in particular, indicating boredom or distraction.
Observant and Alert: Head turning to scan the surroundings, eyes alert and watchful.
Slouched and Disinterested: Poor posture, slumping, showing a lack of energy or disinterest.
Playful and Bouncy: Unable to stand still, bouncing on heels or toes, radiating energy or excitement.
Weary or Fatigued: Slight slumping, perhaps leaning on something for support, indicating tiredness.
Withdrawn: Standing slightly away from others, perhaps with arms holding their own body, showing shyness or desire for solitude.
Intrigued or Curious: Body leaning forward slightly, head tilted, showing interest or curiosity.
Guarded and Wary: Body turned at an angle, possibly creating a barrier with an arm or object, indicating caution or mistrust.
Artistic or Dreamy: Head tilted, possibly looking up or to the side, a faraway look in their eyes, suggesting creativity or daydreaming.
Hands-On Approach: Hands are either clasped behind the back or engaged in some activity, even minor, like fiddling with a watch or ring, indicating a proactive or engaged attitude.
Pensive or Thoughtful: Chin resting on hand, or finger tapping against lips, reflecting deep in thought.
Approachable and Friendly: A gentle smile, body open and facing towards others, indicating openness and friendliness.
