AI Song Generator From Your Own Lyrics: How to Write Lines AI Sings Well

When you use an AI song generator with your own lyrics, most of the problems you hear (rushed lines, swallowed words, a chorus that never quite lands, a name sung wrong) trace back to how the lyrics are written, not to the prompt. The model has to fit every line into a musical phrase it writes itself, so a lyric sheet that reads well on paper can still sing badly. The fixes are mechanical, and you can make most of them before you generate a single take.

Key Takeaways

• Aim for 6 to 10 syllables per line, and keep lines in matching positions within one or two syllables of each other.
• Budget roughly 2 to 3 sung words per second of audio. If you're over, cut lines or raise the duration.
• Paste the full chorus lyrics every time it repeats. In our testing, shortcuts like "(repeat chorus)" or "x2" get sung, not expanded.
• Put only section tags and sung words in the lyrics field. Titles and notes like "(softly)" can end up sung.
• Write numbers, symbols and acronyms the way they should sound, and respell names phonetically.
• Fix one bad line by revising its section, not by regenerating the whole song.

This article is about the words on the page. For the full workflow from lyric sheet to exported track (style prompt, settings, batches, export), see how to turn lyrics into a song with AI. The examples here use the two models in Song Creator Pro, ACE-Step 1.5 and YuE2, and we only describe their behavior where the official docs or our own published guides back it up. Most of the advice applies to cloud generators like Suno too.

Why Lyrics That Read Well Can Sing Badly

On paper, a line can be as long as you like. Sung, it has to fit a phrase of music, and the model decides how long that phrase is. When a line has more syllables than the phrase comfortably holds, the vocal crams them in and the words blur. When lines in matching positions have very different lengths, the melody the model writes for one doesn't fit the next.

YuE2 makes this especially visible. It plans a melody and chords for your song before it renders any audio, so your lyrics are literally set to notes. A line that doesn't fit its notes gets rushed or stretched. ACE-Step 1.5 works differently under the hood, but its official tutorial gives the same advice about line length, as you'll see below.

The good news is that a lyric sheet written with this in mind usually gets better takes across the board, and in either model.

Keep Lines Short and Even

The most concrete number in either model's official documentation is this one from the ACE-Step 1.5 tutorial: 6 to 10 syllables per line usually works best. It adds that lines in the same position (the first line of verse one and the first line of verse two, for example) should stay within about one or two syllables of each other.

For YuE2, the most-cited trick among early users is the same idea applied to repeats: when a line comes back, keep its syllable count matched, because the melody was planned around the first version. YuE2's own cover documentation says the same for translated lyrics: match phrasing and syllable counts to the melody.

In practice:

• Count syllables, not words. "Everything" is one word and four syllables.
• Split long lines. A 15-syllable line almost always works better as two lines of 7 and 8.
• Match your verses to each other. If verse one's lines run 8, 8, 9, 8, aim for something close in verse two.
• Don't write a line you can't sing in one breath. The ACE-Step tutorial lists "no breathing room" among the signs of lyrics that come out sounding machine-made. Read every line aloud at the tempo you imagine. If you run out of air, the vocal will too.

Match the Amount of Lyrics to the Song Length

The other way to get rushed vocals is to give the model more lines than the song has time for. Our ACE-Step prompting guide puts the comfortable rate at roughly 2 to 3 words per second of sung audio; more than that and vocals start to sound rushed and garbled. Remember that intros, instrumental breaks and outros take time too, so the sung parts have less room than the total duration suggests.

Two ways to fix an overloaded song:

1. Cut lines. Four to six lines per section is a reliable range with YuE2, according to early users. A verse that runs past eight lines is usually two verses.
2. Make it longer. Raise the Duration setting so the same words get more room.

The opposite problem exists too. Two short verses and a chorus in a four-minute song leaves long stretches with nothing to sing, and the model fills them however it likes.

Repeat the Chorus Exactly

A chorus works because it comes back. For an AI generator, repetition has a practical benefit as well: the model gets the same words and can treat them as the same section.

• Write it out in full every time. In our testing, and in what other users have reported, YuE2 does not expand shorthand like "(repeat chorus)" or "Chorus x2"; it tries to sing those words. Writing the chorus out is the safe habit with any model.
• Keep it word for word. A small change in the third chorus is a nice idea in a human recording; with a model it mostly means a mismatch with the melody it already wrote. If you do vary it, keep the syllable count the same.
• Keep the hook short. Choruses built on one short phrase that repeats with small changes tend to come out more reliably than four dense, unique lines. Our rap song guide shows the same pattern for hooks.

Rhyme at the Ends of Lines

You don't need to rhyme. But if you do, end rhymes are the ones that tend to come through, because the end of a line is where the vocal naturally lands and holds. Internal rhymes and precise stresses inside a line are much harder to control, since delivery is interpreted, not scripted.

Two cautions from the ACE-Step tutorial's list of what makes lyrics sound AI-written: inconsistent rhyme patterns, and forced rhymes that break the meaning of the line. If the only word that rhymes makes the line nonsense, change the other line or drop the rhyme. A clear, slightly imperfect rhyme sings better than a perfect one that confuses the sentence.

Use a Few Standard Section Tags

Section tags in square brackets tell the model where verses, choruses and bridges are (if those parts are new to you, start with song structure explained). Both official model docs use them, and the ACE-Step tutorial calls them the most powerful tool in the lyrics field. The safe set works in both models:

[Intro]
[Verse]
[Pre-Chorus]
[Chorus]
[Bridge]
[Outro]

Put each tag on its own line and leave a blank line between sections. Beyond that, the two models differ, so check which one you're using:

In the lyrics field	ACE-Step 1.5	YuE2
Standard section tags	Yes	Yes
Tag modifiers like [Chorus - anthemic]	Yes, keep them short	Stick to plain tags
Extra tags like [Instrumental], [Build], [Drop], [Guitar Solo]	Yes	Not documented; for an instrumental intro, use an empty [Intro]
Words in (parentheses)	Treated as background vocals or harmonies	Sung like any other words
UPPERCASE words	Sung with more intensity	Not documented
Notes, titles, stage directions	Leave out	Leave out

The ACE-Step tutorial also warns against piling on tags: keep them concise and put style descriptions in the description field, because too many tags can lead the model to sing the tag text. For the full tag reference per model, see the AI music prompting guide (ACE-Step) and the YuE2 prompting guide.

Keep Everything Unsung Out of the Lyrics Field

This rule causes more ruined takes than any other: the lyrics field should hold only section tags and the words you want sung. YuE2's official agent guide says to keep implementation notes out of the lyrics, and our YuE2 guide explains why: anything in that field gets planned as syllables to sing. "(guitar solo)" is not a stage direction to the model. It's three syllables.

Common things to delete before you paste:

• The song title at the top
• Production notes like "(drums come in)", "(softly)", "(pause)"
• Shorthand like "(repeat chorus)" or "x2"
• Chord symbols copied from a lyric sheet
• Speaker labels like "Her:" or "Both:"

If you want something to happen musically, describe it in the style prompt or, with ACE-Step, use a section tag like [Instrumental] or a short modifier.

Words AI Vocalists Mispronounce (and How to Respell Them)

Neither model gives you a pronunciation control. YuE2's official documentation states it has no phoneme-alignment argument, and the ACE-Step tutorial offers no phoneme syntax. The only lever you have is spelling: the model sings what the letters suggest. That makes certain kinds of words reliably risky.

Risky word type	Example	What to try
Numbers and digits	24/7, 1999, 3am	Write them as words: "twenty-four seven", "nineteen ninety-nine", "three a.m." or "three in the morning"
Symbols	&, %, @, #	Write the word: "and", "percent", "at"
Abbreviations and acronyms	NYC, DJ, ASAP	Write how you want it said: "New York City", "dee jay", "A-S-A-P" or "as soon as possible"
Words spelled the same but said differently	live, read, lead, tear, wind, bass	Swap for an unambiguous word, or respell: "liv" or "lyve", "red" or "reed"
Names, brands, invented words	Siobhan, Nguyen, place names	Respell phonetically: "Shivawn"
Slang and dropped letters	goin', 'cause, y'all	Usually fine, but if apostrophes trip it up, try "goin" or "cuz"
Long vowels you want held	"yeah", "love"	ACE-Step's tutorial allows repeating vowels ("loooove") but warns the effect is unstable and sometimes mispronounced; use sparingly

Treat respelling as an experiment, not a guarantee. A respelling that works in one take can come out differently in the next, and the two models may disagree. Change one word, generate a small batch, and listen. Two more practical notes:

• Avoid hyphenating syllables ("ne-ver-more") to force pronunciation. Our YuE2 guide flags it as unreliable; write words normally and respell the whole word instead.
• Keep two copies of your lyrics. The respelled version goes into the generator; the clean version is what you publish, print, or submit to a distributor.

Language matters here too. A word from one language inside lyrics in another is a common source of odd pronunciation. YuE2 sings English, Mandarin, Japanese and Korean; ACE-Step 1.5 supports 50+ languages. Write the lyrics in the language you want sung, and match the language setting: for ACE-Step, set the Language field; for YuE2, name the language in the style description.

Fixing a Line That Was Sung Badly

When one line comes out wrong in a take you otherwise like, the instinct is to regenerate the whole song. That throws away everything that worked, and the next take will have its own problems. Diagnose first, then fix the smallest thing that solves it.

What you hear	Likely cause	Fix
Line is wrong in one take only	Bad luck on that take	Pick another take from the batch, or generate more
Line is rushed or blurred in every take	Too many syllables for the phrase	Shorten the line or split it, keeping its length close to its neighbors
Same word mispronounced in every take	Spelling is ambiguous to the model	Respell it (see the table above)
Words sung that you didn't write	Notes, titles or shorthand in the lyrics field	Delete everything that isn't a section tag or a sung word
A line is skipped	Too many lines for the duration	Cut lines or raise Duration
The section has the wrong energy	Description or tag doesn't support it	Adjust the description; with ACE-Step, try a tag modifier

If the take is worth keeping, fix the line with Revise rather than starting over. Revise regenerates a selected stretch of the song and leaves the rest alone:

1. Click Revise on the take, or load the file in the Revise tab. Revise runs on ACE-Step 1.5 and accepts any audio, including a YuE2 song.
2. Drag the handles on the waveform to select just the section with the bad line. Revise works on stretches between 3 and 90 seconds.
3. Paste the full lyrics with the same section tags, and change only the line you're fixing.
4. Keep Revise Strength around 0.4 to 0.6 and generate 2 or 3 versions. Keep the one that blends in best.

Revise blends best when the new line has about the same length as the old one, which is one more reason to fix rushed lines by trimming a syllable or two rather than rewriting the whole verse. The ACE-Step tutorial describes this kind of edit as changing the lyric content while keeping the melody and arrangement. The full walkthrough, including the crossfade settings, is in how to revise part of a song with AI.

Before and After: One Verse, Rewritten

Here is a verse as many people would first write it:

[Verse]
I've been thinking about everything that happened last December when you left
And the way the 2 of us would talk till 3am
I still can't believe it, I keep reading every text
(softly) Maybe I'll get over it someday

What goes wrong: the first line is around 20 syllables and is likely to come out rushed; "2" and "3am" are digits; "(softly)" will be sung (YuE2) or treated as a background vocal (ACE-Step); and the line lengths are all over the place.

The same verse, rewritten for the model:

[Verse]
I keep thinking of December
When you walked out in the snow
How the two of us would talk
Till three o'clock, soft and low

Four lines of 7 or 8 syllables, no digits, no notes, and an end rhyme on lines two and four. If you want the verse sung softly, say so in the description ("intimate, soft verses, powerful chorus") instead of in the lyrics.