Existing accent normalization methods do not typically offer control over accent strength, yet many applications—such as language learning and dubbing—require tunable accent retention. We propose DLM-AN, a controllable accent normalization system built on masked discrete diffusion over self-supervised speech tokens. A Common Token Predictor identifies source tokens that likely encode native pronunciation; these tokens are selectively reused to initialize the reverse diffusion process. This provides a simple yet effective mechanism for controlling accent strength: reusing more tokens preserves more of the original accent. DLM-AN further incorporates a flow-matching Duration Ratio Predictor that automatically adjusts the total duration to better match the native rhythm. Experiments on multi-accent English data show that DLM-AN achieves the lowest word error rate among all compared systems while delivering competitive accent reduction and smooth, interpretable accent strength control.
You can download all audio files on this page by cloning this github repository.
Each column corresponds to a different speaker utterance and each row to a different system. The first row contains the original accented source audio; subsequent rows show the accent-normalized outputs from various systems.
Naming convention: -1 systems are duration-free (no total-duration constraint); -2 systems are duration-controlled (preserving the source total duration).
DLM-AN-2 threshold: Controls accent strength via token reuse — threshold = 1.0 generates entirely from scratch (strongest normalization), while threshold = 0.0 resynthesizes with all source tokens (original accent preserved).
| ABA (Arabic) | YBAA (Arabic) | ZHAA (Arabic) | SKA (Arabic) | RRBI (Hindi) | TNI (Hindi) | ASI (Hindi) | SVBI (Hindi) | ERMS (Spanish) | EBVS (Spanish) | NJS (Spanish) | MBMPS (Spanish) | LXC (Chinese) | BWC (Chinese) | NCC (Chinese) | TXHC (Chinese) | HJK (Korean) | YDCK (Korean) | YKWK (Korean) | HKK (Korean) | HQTV (Vietnamese) | PNV (Vietnamese) | THV (Vietnamese) | TLV (Vietnamese) | BDL (American) | RMS (American) | SLT (American) | CLB (American) | ABA (Arabic) | YBAA (Arabic) | ZHAA (Arabic) | SKA (Arabic) | RRBI (Hindi) | TNI (Hindi) | ASI (Hindi) | SVBI (Hindi) | ERMS (Spanish) | EBVS (Spanish) | NJS (Spanish) | MBMPS (Spanish) | LXC (Chinese) | BWC (Chinese) | NCC (Chinese) | TXHC (Chinese) | HJK (Korean) | YDCK (Korean) | YKWK (Korean) | HKK (Korean) | HQTV (Vietnamese) | PNV (Vietnamese) | THV (Vietnamese) | TLV (Vietnamese) | BDL (American) | RMS (American) | SLT (American) | CLB (American) | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Text |
I was brought up the way most girls in Hawaii are brought up |
I want to know how all this is possible |
Without them he could not run his empire |
The other felt a sudden wave of irritation rush through him |
I had been born with no organic chemical predisposition toward alcohol |
But there came no promise from the bow of the canoe |
They likewise are disinclined to being eaten |
But he reconciled himself to it by an act of faith |
Bassett was a fastidious man |
But Martin smiled a superior smile |
I never allow what can't be changed to annoy me |
All operations have been carried on from Montreal and Toronto |
It was his intention to return to Eileen and her father |
Do you know that you are shaking my confidence in you |
His immaculate appearance was gone |
They are his tongue by which he makes his knowledge articulate |
It occurred to me that there would have to be an accounting |
It was beating and waiting in the ambush of those black pits |
Suddenly his fingers closed tightly over the handkerchief |
There's not an iota of truth in it |
He moved away as quietly as he had come |
The girl faced him her eyes shining with sudden fear |
He saw only the effect in a general sketchy way |
Down there the earth was already swelling with life |
Thus had the raw wilderness prepared him for this day. |
It was not a large lake, and almost round. |
He was smooth-shaven, and his hair and eyes were black. |
One by one the boys were captured. |
From my earliest recollection my sleep was a period of terror |
Of course much grumbling went on and little outbursts were continually occurring |
He caught himself with a jerk |
He looked like one who had passed through an uncomfortable hour or two |
The steward has just tendered me a respectful bit of advice |
There is not an iota of truth in it certainly not |
The very thought of the effort to swim over was nauseating |
He was sure now of but few things |
Besides had he not whipped the big owl in the forest |
Philip knew that she was not an Indian |
She is essentially the life giving life conserving female of the species |
Philip bent low over Pierre |
Scarcely had he uttered the name when Pierre's closing eyes shot open |
They edged nearer and stood shoulder to shoulder facing their world |
In her haste to get away she had forgotten these things |
But how are you going to do it |
A bush chief had died a natural death |
What an excited whispering and conferring took place |
He made sure that the magazine was loaded and resumed his paddling |
But already he had composed himself |
Obviously it was a disease that could be contracted by contact |
It lived in perpetual apprehension of that quarter of the compass |
To my dearest and always appreciated friend I submit myself |
I just do appreciate it without being able to express my feelings |
Now, you understand. |
They will search for us between their camp and Churchill. |
I was sick once -- typhoid. |
Mab, she said. |
| Source | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| TokAN-1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| TokAN-2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| CosyAccent-1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| CosyAccent-2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DLM-AN-1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DLM-AN-2 (Threshold=1.0) |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DLM-AN-2 (Threshold=0.3) |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| DLM-AN-2 (Threshold=0.0) |
↔ Scroll horizontally to explore additional columns.
This panel demonstrates smooth accent strength control by varying the proportion of source tokens reused during generation. A higher proportion retains more of the original accent; a lower proportion yields stronger normalization.
| ABA (Arabic) | YBAA (Arabic) | ZHAA (Arabic) | SKA (Arabic) | RRBI (Hindi) | TNI (Hindi) | ASI (Hindi) | SVBI (Hindi) | ERMS (Spanish) | EBVS (Spanish) | NJS (Spanish) | MBMPS (Spanish) | LXC (Chinese) | BWC (Chinese) | NCC (Chinese) | TXHC (Chinese) | HJK (Korean) | YDCK (Korean) | YKWK (Korean) | HKK (Korean) | HQTV (Vietnamese) | PNV (Vietnamese) | THV (Vietnamese) | TLV (Vietnamese) | BDL (American) | RMS (American) | SLT (American) | CLB (American) | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Text |
From my earliest recollection my sleep was a period of terror |
He was sure now of but few things |
There's not an iota of truth in it |
I was brought up the way most girls in Hawaii are brought up |
I had been born with no organic chemical predisposition toward alcohol |
They will search for us between their camp and Churchill |
They likewise are disinclined to being eaten |
He looked like one who had passed through an uncomfortable hour or two |
Besides had he not whipped the big owl in the forest |
Philip knew that she was not an Indian |
He moved away as quietly as he had come |
But already he had composed himself |
Scarcely had he uttered the name when Pierre's closing eyes shot open |
Do you know that you are shaking my confidence in you |
His immaculate appearance was gone |
It lived in perpetual apprehension of that quarter of the compass |
A bush chief had died a natural death |
It was his intention to return to Eileen and her father |
He made sure that the magazine was loaded and resumed his paddling |
Bassett was a fastidious man |
Obviously it was a disease that could be contracted by contact |
The girl faced him her eyes shining with sudden fear |
He saw only the effect in a general sketchy way |
Down there the earth was already swelling with life |
Thus had the raw wilderness prepared him for this day. |
It occurred to me that there would have to be an accounting. |
I was sick once -- typhoid. |
One by one the boys were captured. |
| Source | ||||||||||||||||||||||||||||
| Proportion=1.00 (Resynthesis) |
||||||||||||||||||||||||||||
| Proportion=0.90 | ||||||||||||||||||||||||||||
| Proportion=0.70 | ||||||||||||||||||||||||||||
| Proportion=0.50 | ||||||||||||||||||||||||||||
| Proportion=0.30 | ||||||||||||||||||||||||||||
| Proportion=0.10 | ||||||||||||||||||||||||||||
| Proportion=0.00 (From-scratch) |
↔ Scroll horizontally to explore additional columns.
This panel demonstrates accent strength control via thresholding. The Common Token Predictor assigns each source token a probability of being native-like; only tokens whose probability exceeds the threshold are reused.
| ABA (Arabic) | YBAA (Arabic) | ZHAA (Arabic) | SKA (Arabic) | RRBI (Hindi) | TNI (Hindi) | ASI (Hindi) | SVBI (Hindi) | ERMS (Spanish) | EBVS (Spanish) | NJS (Spanish) | MBMPS (Spanish) | LXC (Chinese) | BWC (Chinese) | NCC (Chinese) | TXHC (Chinese) | HJK (Korean) | YDCK (Korean) | YKWK (Korean) | HKK (Korean) | HQTV (Vietnamese) | PNV (Vietnamese) | THV (Vietnamese) | TLV (Vietnamese) | BDL (American) | RMS (American) | SLT (American) | CLB (American) | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Text |
From my earliest recollection my sleep was a period of terror |
He was sure now of but few things |
There's not an iota of truth in it |
I was brought up the way most girls in Hawaii are brought up |
I had been born with no organic chemical predisposition toward alcohol |
They will search for us between their camp and Churchill |
They likewise are disinclined to being eaten |
He looked like one who had passed through an uncomfortable hour or two |
Besides had he not whipped the big owl in the forest |
Philip knew that she was not an Indian |
He moved away as quietly as he had come |
But already he had composed himself |
Scarcely had he uttered the name when Pierre's closing eyes shot open |
Do you know that you are shaking my confidence in you |
His immaculate appearance was gone |
It lived in perpetual apprehension of that quarter of the compass |
A bush chief had died a natural death |
It was his intention to return to Eileen and her father |
He made sure that the magazine was loaded and resumed his paddling |
Bassett was a fastidious man |
Obviously it was a disease that could be contracted by contact |
The girl faced him her eyes shining with sudden fear |
He saw only the effect in a general sketchy way |
Down there the earth was already swelling with life |
Thus had the raw wilderness prepared him for this day. |
It occurred to me that there would have to be an accounting. |
I was sick once -- typhoid. |
One by one the boys were captured. |
| Source | ||||||||||||||||||||||||||||
| Threshold=0.00 (Resynthesis) |
||||||||||||||||||||||||||||
| Threshold=0.01 | ||||||||||||||||||||||||||||
| Threshold=0.10 | ||||||||||||||||||||||||||||
| Threshold=0.30 | ||||||||||||||||||||||||||||
| Threshold=0.50 | ||||||||||||||||||||||||||||
| Threshold=0.70 | ||||||||||||||||||||||||||||
| Threshold=0.90 | ||||||||||||||||||||||||||||
| Threshold=0.99 | ||||||||||||||||||||||||||||
| Threshold=1.00 (From-scratch) |
↔ Scroll horizontally to explore additional columns.
This panel showcases DLM-AN's ability to control the total duration of generated speech. The Duration Ratio Predictor scales the source utterance length by a given factor: ×0.75 produces faster speech, ×1.0 preserves the original duration, and ×1.25 produces slower speech — all while maintaining the same level of accent normalization.
| ABA (Arabic) | YBAA (Arabic) | ZHAA (Arabic) | SKA (Arabic) | RRBI (Hindi) | TNI (Hindi) | ASI (Hindi) | SVBI (Hindi) | ERMS (Spanish) | EBVS (Spanish) | NJS (Spanish) | MBMPS (Spanish) | LXC (Chinese) | BWC (Chinese) | NCC (Chinese) | TXHC (Chinese) | HJK (Korean) | YDCK (Korean) | YKWK (Korean) | HKK (Korean) | HQTV (Vietnamese) | PNV (Vietnamese) | THV (Vietnamese) | TLV (Vietnamese) | BDL (American) | RMS (American) | SLT (American) | CLB (American) | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Text |
From my earliest recollection my sleep was a period of terror |
He was sure now of but few things |
There's not an iota of truth in it |
I was brought up the way most girls in Hawaii are brought up |
I had been born with no organic chemical predisposition toward alcohol |
They will search for us between their camp and Churchill |
They likewise are disinclined to being eaten |
He looked like one who had passed through an uncomfortable hour or two |
Besides had he not whipped the big owl in the forest |
Philip knew that she was not an Indian |
He moved away as quietly as he had come |
But already he had composed himself |
Scarcely had he uttered the name when Pierre's closing eyes shot open |
Do you know that you are shaking my confidence in you |
His immaculate appearance was gone |
It lived in perpetual apprehension of that quarter of the compass |
A bush chief had died a natural death |
It was his intention to return to Eileen and her father |
He made sure that the magazine was loaded and resumed his paddling |
Bassett was a fastidious man |
Obviously it was a disease that could be contracted by contact |
The girl faced him her eyes shining with sudden fear |
He saw only the effect in a general sketchy way |
Down there the earth was already swelling with life |
Thus had the raw wilderness prepared him for this day. |
It occurred to me that there would have to be an accounting. |
I was sick once -- typhoid. |
One by one the boys were captured. |
| Source | ||||||||||||||||||||||||||||
| Duration x0.75 | ||||||||||||||||||||||||||||
| Duration x1.0 | ||||||||||||||||||||||||||||
| Duration x1.25 |
↔ Scroll horizontally to explore additional columns.