Evaluation
Evaluated on a deterministic held-out set of 3,000 pairs (seed=42), decoded
greedily (do_sample=False), scored with sacreBLEU:
Table with columns: Metric, Score| Metric | Score |
|---|
| sacreBLEU | 24.35 |
| chrF | 52.38 |
The saved weights are the best checkpoint by validation loss (eval_loss=1.271,
epoch 2 of 3).
Example translations
Real greedy-decoded outputs from the held-out set (English → model output):
Table with columns: English, Model output (Egyptian Arabic)| English | Model output (Egyptian Arabic) |
|---|
| Man, these things happen. Sometimes Liverpool loses the match, and other times Real Madrid wins it. | يا عم الحاجات دي بتحصل. ساعات ليفربول يخسر الماتش، وساعات ريال مدريد يكسبها. |
| I want grilled chicken, kofta on charcoal, and Pepsi. | أنا عايز فراخ مشوية وكفتة على الفحم وبابسي. |
| So, do we have to pay here? | يعني لازم ندفع هنا؟ |
| I will be fine, don't worry | أنا هبقى كويس، متقلقش |
| What's my standard anyway? Forget about his standards, the awards' standards, and all that stuff. | إيه المعيار بتاعي أصلاً؟ سيبك من درجاته، معايير الجوائز، وكل الكلام ده. |
| Check yourself, Mr. Harry. You destroyed Tottenham Club—looks like you were the problem. | بص على نفسك يا أستاذ هاري. انت دمرت نادي توتنهام، شكلك كنت المشكلة. |
| Let's go, I'll get up, go to Rouh El Nagham, and call you on the phone. | يلا بينا، أنا هقوم، هقوم لروح النغم، وأكلمك في التليفون. |
| My question is, what kind of work is Guardiola doing with this one and that one? Where did he succeed? | سؤالي هو ايه الشغل اللي جوارديولا بيعمله مع ده وده؟ هو نجح فين؟ |
A larger set of 20 examples (with references) is included in
eval_translation.json.
Usage
The model uses a ChatML prompt format with a fixed system instruction.
import torch
from transformers import AutoModelForCausalLM, AutoTokenizer
model_id = "oddadmix/50M-Egyptian-Translation-v1"
tok = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(model_id, dtype=torch.bfloat16).to("cuda").eval()
SYSTEM = "أنت مترجم محترف. ترجم النص الإنجليزي إلى اللهجة المصرية العامية."
def translate(english: str) -> str:
prompt = (
f"<|im_start|>system\n{SYSTEM}<|im_end|>\n"
f"<|im_start|>user\n{english.strip()}<|im_end|>\n"
f"<|im_start|>assistant\n"
)
ids = tok(prompt, return_tensors="pt", add_special_tokens=False).to(model.device)
if tok.bos_token_id is not None:
bos = torch.tensor([[tok.bos_token_id]], device=model.device)
ids["input_ids"] = torch.cat([bos, ids["input_ids"]], dim=1)
ids["attention_mask"] = torch.cat([torch.ones_like(bos), ids["attention_mask"]], dim=1)
out = model.generate(**ids, max_new_tokens=256, do_sample=False,
eos_token_id=tok.eos_token_id, pad_token_id=tok.pad_token_id)
return tok.decode(out[0, ids["input_ids"].size(1):], skip_special_tokens=True).strip()
print(translate("Man, these things happen. Sometimes Liverpool loses the match."))
Training
- Base model:
oddadmix/50M-2048-Emhotob (Llama arch, ~51.8M params)
- Dataset:
oddadmix/egyptian-translation-dataset-2.9-openai-batch (135K English/Egyptian-Arabic pairs)
- Method: HuggingFace
Trainer, ChatML format, prompt-masked cross-entropy
(loss only on the Arabic assistant turn). Two ChatML special tokens
(<|im_start|>, <|im_end|>) were added and the embeddings resized.
- Hyperparameters: 3 epochs · effective batch 64 · LR 3e-4 (cosine, 5% warmup) ·
bf16 · max length 1024 ·
load_best_model_at_end on eval_loss.
- Split: 132,282 train / 3,000 deterministic held-out eval (
seed=42).
Out-of-domain evaluation — Egyptian Arabic Translation Benchmark
The results above are in-domain: a held-out split of the same corpus this model was
trained on. The numbers below are out-of-domain — the same model scored on the
Egyptian Arabic Translation Benchmark
(oddadmix/egyptian-arabic-translation-benchmark, 319 English→Egyptian pairs written by a different annotator with different
orthographic conventions).
Expect these to be substantially lower than the in-domain scores. That gap is the
generalization penalty, not a regression — both numbers are real, they measure different things.
Table with columns: Metric, Score| Metric | Score |
|---|
BLEU (evaluate, 0–1 — leaderboard metric) | 0.1261 |
| BLEU (sacrebleu, 0–100) | 12.61 |
| chrF | 46.13 |
| METEOR | 0.3559 |
Decoding is deterministic greedy (do_sample=False, no repetition penalty), using the
exact ChatML prompt format the model was trained with — the same protocol as every other
number in this study.
Where this rung sits
Table with columns: Model, Params, BLEU (hf), BLEU (sacre), chrF, METEOR| Model | Params | BLEU (hf) | BLEU (sacre) | chrF | METEOR |
|---|
| 5M v1 | 5.2M | 0.0000 | 0.19 | 13.00 | 0.0558 |
| 5M v2 | 5.2M | 0.0108 | 1.08 | 22.19 | 0.1352 |
| 10M v1 | 11.2M | 0.0313 |
Reading these numbers
BLEU understates quality on this set. Scoring is against a single reference, so a correct
translation that picks a different valid word is penalized — e.g. فريش vs the reference's
طازة for "fresh", or التليفون اللي ضاع vs تليفونها الضايع for "her lost phone". Both are
good Egyptian; only one matches the reference. chrF and METEOR track perceived quality more
closely here.
At 319 rows, differences of roughly 1–2 BLEU between adjacent rungs are within noise.
These are small models — 5M to 50M parameters, orders of magnitude below the large systems
typically evaluated on this benchmark. The result of interest is the scaling curve and
per-parameter efficiency, not absolute rank against models 100–1000× the size.
Limitations
- A 50M model: expect errors on rare / technical vocabulary and occasional
repetition loops on longer generations (mitigate with
repetition_penalty
and no_repeat_ngram_size at inference).
- Trained on conversational Egyptian; other Arabic dialects or formal MSA are
out of scope.
- Gender is disambiguated only from context, so it may default to masculine for
ambiguous English inputs.
License
Apache-2.0, inherited from the base model.