Accent normalization (AN) systems often struggle with unnatural outputs and undesired content distortion, stemming from both suboptimal training data and rigid duration modeling. In this paper, we propose a "source-synthesis" methodology for training data construction. By generating source L2 speech and using authentic native speech as the training target, our approach avoids learning from TTS artifacts and, crucially, requires no real L2 data in training. Alongside this data strategy, we introduce CosyAccent, a non-autoregressive model that resolves the trade-off between prosodic naturalness and duration control. CosyAccent implicitly models rhythm for flexibility yet offers explicit control over total output duration. Experiments show that, despite being trained without any real L2 speech, CosyAccent achieves significantly improved content preservation and superior naturalness compared to strong baselines trained on real-world data.
You can download all audio files on this page by cloning this github repository.
In this panel, random samples from the testing set are presented.
| Speaker | BWC (Chinese) | BWC (Chinese) | LXC (Chinese) | LXC (Chinese) | NCC (Chinese) | NCC (Chinese) | TXHC (Chinese) | TXHC (Chinese) | ASI (Hindi) | ASI (Hindi) | RRBI (Hindi) | RRBI (Hindi) | SVBI (Hindi) | SVBI (Hindi) | TNI (Hindi) | TNI (Hindi) | ABA (Arabic) | ABA (Arabic) | SKA (Arabic) | SKA (Arabic) | YBAA (Arabic) | YBAA (Arabic) | ZHAA (Arabic) | ZHAA (Arabic) | HJK (Korean) | HJK (Korean) | HKK (Korean) | HKK (Korean) | YDCK (Korean) | YDCK (Korean) | YKWK (Korean) | YKWK (Korean) | EBVS (Spanish) | EBVS (Spanish) | ERMS (Spanish) | ERMS (Spanish) | MBMPS (Spanish) | MBMPS (Spanish) | NJS (Spanish) | NJS (Spanish) | HQTV (Vietnamese) | HQTV (Vietnamese) | PNV (Vietnamese) | PNV (Vietnamese) | BDL (American) | BDL (American) | CLB (American) | CLB (American) | RMS (American) | RMS (American) | SLT (American) | SLT (American) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Text |
But Martin smiled a superior smile |
Without them he could not run his empire |
In her haste to get away she had forgotten these things |
From my earliest recollection my sleep was a period of terror |
A rising tide of fat had submerged them |
Miss Brodie's smile was slightly sarcastic |
But already he had composed himself |
He looked like one who had passed through an uncomfortable hour or two |
He moved away as quietly as he had come |
It occurred to me that there would have to be an accounting |
But he reconciled himself to it by an act of faith |
I had been born with no organic chemical predisposition toward alcohol |
I want to know how all this is possible |
They likewise are disinclined to being eaten |
He was smooth shaven and his hair and eyes were black |
There is not an iota of truth in it certainly not |
The girl faced him her eyes shining with sudden fear |
Lots of men take women buggy riding |
They are his tongue by which he makes his knowledge articulate |
His immaculate appearance was gone |
Do you know that you are shaking my confidence in you |
They will search for us between their camp and Churchill |
What an excited whispering and conferring took place |
That is the strange part of it |
The very thought of the effort to swim over was nauseating |
He caught himself with a jerk |
When I can't see beauty in woman I want to die |
They edged nearer and stood shoulder to shoulder facing their world |
I was brought up the way most girls in Hawaii are brought up |
One by one the boys were captured |
Obviously it was a disease that could be contracted by contact |
Your father's fifth command he nodded |
He was sure now of but few things |
Now you understand |
The land exchanged its austere robes for the garb of a smiling wanton |
Philip knew that she was not an Indian |
All an appearance can know is mirage |
Fresh meat they failed to obtain |
All operations have been carried on from Montreal and Toronto |
I just do appreciate it without being able to express my feelings |
Now go ahead and tell me in a straightforward way what has happened |
But how are you going to do it |
But there came no promise from the bow of the canoe |
Down there the earth was already swelling with life |
Philip bent low over Pierre. |
It lived in perpetual apprehension of that quarter of the compass. |
A bush chief had died a natural death. |
Besides, had he not whipped the big owl in the forest. |
The other felt a sudden wave of irritation rush through him. |
Mab, she said. |
Suddenly his fingers closed tightly over the handkerchief. |
He heard a sound which brought him quickly into consciousness of day. |
| Source | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| FramAN | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| TokAN-1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| TokAN-2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| CosyAccent-1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| CosyAccent-2 |
* please scroll horizontally to explore additional columns in the table.
In this panel, the testing samples are relatively long compared to the text, likely due to disfluencies.
| Speaker | BWC (Chinese) | LXC (Chinese) | NCC (Chinese) | TXHC (Chinese) | ABA (Arabic) | YBAA (Arabic) | ZHAA (Arabic) | YDCK (Korean) | YKWK (Korean) | EBVS (Spanish) | MBMPS (Spanish) | NJS (Spanish) | PNV (Vietnamese) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Text |
It occurred to me that there would have to be an accounting |
His immaculate appearance was gone |
His immaculate appearance was gone |
The land exchanged its austere robes for the garb of a smiling wanton |
He was sure now of but few things |
They will search for us between their camp and Churchill |
There is not an iota of truth in it certainly not |
I never allow what can't be changed to annoy me |
He was sure now of but few things |
In her haste to get away she had forgotten these things |
The steward has just tendered me a respectful bit of advice |
He was sure now of but few things |
He was sure now of but few things |
| Source | |||||||||||||
| FramAN | |||||||||||||
| TokAN-1 | |||||||||||||
| TokAN-2 | |||||||||||||
| CosyAccent-1 | |||||||||||||
| CosyAccent-2 |
* please scroll horizontally to explore additional columns in the table.