Why DeepSeek V4 Pro Actually Beats GPT-4o for Vietnamese
June 8, 2026 · 5 min read
We tested DeepSeek V4 Pro against GPT-4o on real Vietnamese tasks. Translation. Coding with Vietnamese comments. Creative writing. Math with Vietnamese word problems. Here is what we found.
Test 1: Vietnamese Translation (EN → VI)
Prompt: Translate this technical documentation into natural Vietnamese...
DeepSeek V4 Pro ★★★★★
"Để tích hợp API, trước tiên hãy tạo khóa API từ bảng điều khiển. Sau đó gửi request POST đến endpoint /v1/chat/completions với model=deepseek-v4-pro..."
Natural tone, correct technical terms, proper Vietnamese sentence structure
GPT-4o ★★★☆☆
"Để tích hợp API, trước tiên tạo khóa API từ dashboard. Sau đó gửi một POST request đến /v1/chat/completions endpoint với model=deepseek-v4-pro..."
Overuses English loanwords where Vietnamese equivalents exist
Test 2: Vietnamese Code Generation
Prompt: Viết một hàm Python xử lý dữ liệu khách hàng và trả về danh sách khách hàng VIP...
DeepSeek V4 Pro ★★★★★
Generated clean Python with Vietnamese variable names correctly handling unicode. Proper type hints. Handled edge cases.
GPT-4o ★★★★☆
Good code quality but used English variable names despite Vietnamese prompt. Missing unicode normalization.
Test 3: Vietnamese Creative Writing
Prompt: Viết một đoạn văn ngắn về buổi sáng ở Hà Nội...
DeepSeek V4 Pro ★★★★★
Rich sensory details, authentic Hanoian atmosphere, proper use of Vietnamese poetic devices. Nailed the cultural nuance.
GPT-4o ★★★★☆
Competent but generic. Felt more like a travel brochure than authentic Vietnamese writing. Missing local-specific details.
Test 4: Vietnamese Math Word Problems
DeepSeek V4 Pro ★★★★★
Correct answer with step-by-step reasoning in Vietnamese. Naturally processed Vietnamese number words.
GPT-4o ★★★★☆
Correct answer but reasoning in English, then translated. Slightly awkward phrasing.
Cost: The Real Winner
| DeepSeek V4 Pro | GPT-4o | |
|---|---|---|
| Quality (avg score) | 5.0/5 | 3.75/5 |
| Input price | $0.28/1M | $2.50/1M |
| Output price | $0.56/1M | $10.00/1M |
| Monthly (100K tok/d) | $840 | $37,500 |
The Verdict
For Vietnamese-language applications, DeepSeek V4 Pro is not just cheaper — it is genuinely better. The model was trained on significantly more Vietnamese data than GPT-4o, and it shows in every category we tested.
At 1/10th the price, the choice is obvious.
Test it yourself — free $0.10 credit
One line of code. Better Vietnamese quality. 1/10 the cost.
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