Multilingual Data Annotation
Services for AI & NLP Training

LanguageMark provides professional multilingual data annotation services across 197+ languages — covering text, audio, image, and video annotation for AI and machine learning teams. Every annotation is performed by native-speaking linguists with domain expertise in the target language and subject area — not crowd workers or general-purpose labelers.
 
Based in New Delhi and Bhopal, we are one of the very few annotation providers in India that covers all 22 official Indian languages with professional linguistic oversight. We have been building language datasets and delivering annotation services to AI teams and enterprise organisations since 2014.
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Sentiment and intent labels that reflect the annotator’s background, not the target market’s conventions.

Annotations based on standard written language that fail on the colloquial or regional registers your users actually produce.

Generic annotators labeling medical, legal, or financial content without subject-matter knowledge.

Multilingual or mixed-language text (like Hinglish) that general annotators cannot handle reliably without native bilingual expertise.

Why Multilingual Annotation Requires Linguistic Expertise — Not Just Labelers

Annotation for English NLP is well-served by general-purpose labeling platforms. Annotation for multilingual AI — particularly for Indian languages, low-resource languages, and domain-specific content — is a fundamentally different problem.

The failure modes in multilingual annotation are systematic, not random. A labeler who speaks Hindi but does not understand medical terminology will produce sentiment labels that are linguistically correct but clinically wrong. A labeler who annotates Bengali text without understanding regional dialect variation will produce NER labels that fail on real-world data distributions. A crowd worker annotating intent for a Hindi customer service chatbot who is not a native speaker of colloquial urban Hindi will mislabel at rates that make the model unreliable.

LanguageMark solves this by treating annotation as a linguistics problem first. Every annotation project is assigned to native-speaking linguists with domain expertise in the relevant subject area. Quality is built in through a five-stage process — not added as a final check after 50,000 items have been labeled.
 

 

Our Data Annotation Services

Eight annotation service types — all available in 197+ languages, all performed by domain-specialist native speakers.

Text Annotation & NLP Labeling

Sentiment analysis, intent classification, named entity recognition (NER), relation extraction, coreference resolution, semantic similarity, and document classification — in 197+ languages. Annotators are native speakers with domain knowledge in the subject area being labeled.

Named Entity Recognition (NER)

Identification and classification of named entities in text — people, organisations, locations, dates, product names, medical terms, legal references, and custom entity types. Available in all major Indian languages, global languages, and code-mixed text where standard NER tools consistently fail.

Sentiment & Intent Annotation

Sentence-level, aspect-level, and document-level sentiment labeling — positive, negative, neutral, and nuanced emotion categories. Intent annotation for conversational AI and customer service automation. Culturally calibrated by native speakers to reflect how sentiment is actually expressed in the target language.

Transcription verification, speaker diarization, emotion annotation, phoneme labeling, accent classification, and prosody annotation for speech recognition and voice AI training. Available in all major Indian languages and global languages — with dialect and accent coverage that standard annotation platforms cannot provide.

Image Annotation

Object detection (bounding boxes), semantic segmentation, instance segmentation, image classification, keypoint annotation, and polygon annotation. Culturally appropriate labeling for non-Western visual contexts — annotators are briefed on the target market’s visual conventions before work begins.

Video Annotation

Frame-by-frame object tracking, action recognition labeling, activity detection, event annotation, and video classification. Consistent annotation across extended video sequences with quality sampling throughout — not only at final delivery.

LLM Evaluation & RLHF Data

Human preference ranking, response quality evaluation, safety and alignment annotation, and instruction-following assessment for LLM fine-tuning and RLHF. Evaluators are domain-trained and language-native — producing feedback that reflects real user expectations in each target language and market.

Data Classification & Labeling

Categorisation of structured and unstructured data — content moderation labels, topic classification, document type labeling, spam detection, and multi-class classification for training supervised learning models. Custom taxonomy development included for projects with non-standard label sets.

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Annotation Across All 22 Indian
Languages — With Dialect Coverage

Most annotation vendors cover English well and offer limited support for a handful of Indian languages as an afterthought. Building AI that actually works for Indian users — not just transliterated-English products — requires annotation built from the ground up by people who live in those languages.
 
 
LanguageMark has been working in Indian languages professionally since 2014. Our annotation network covers all 22 constitutionally recognised Indian languages, regional dialect variants, and the code-mixed Hindi-English patterns that characterise real Indian digital communication. When you annotate sentiment in Hinglish with a non-native annotator, you get models that misfire on the majority of what Indian users actually type. We solve that problem specifically.
 
 
 

All 22 Scheduled Indian Languages

Hindi · Bengali · Telugu · Marathi · Tamil · Urdu · Gujarati · Kannada · Odia · Malayalam · Punjabi · Assamese · Maithili · Santali · Kashmiri · Nepali · Sindhi · Dogri · Konkani · Manipuri · Bodo · Sanskrit

Code-Mixed Variants

Hinglish (Hindi-English) · Tanglish (Tamil-English) · Bengali-English · Telugu-English · and others

 

Global Languages

Arabic · Mandarin · French · German · Spanish · Japanese · Portuguese · Russian · Korean · and 170+ more
 
 

How We Annotate - Quality Built In,
Not Added At the End

Most annotation projects fail not because the tools are wrong but because quality is treated as a final review rather than a design principle. We apply the same HATF™ quality framework to annotation that we apply to all our language work — five defined stages, named reviewers, and measurable quality benchmarks at each step.
 

Step 1 —

Schema design and alignment

Annotation schema, label taxonomy, edge case guidelines, and quality targets documented and agreed before the first item is labeled. We do not begin production annotation until the schema is unambiguous.

Step 2 —

Annotator selection and briefing

Native-speaking, domain-specialist annotators selected per language and subject area. Every annotator is briefed on the schema, reviewed on a calibration batch, and must pass a quality threshold before entering production.

Step 3 —

Pilot batch and inter-annotator agreement

A pilot of 200–500 items is annotated, measured for inter-annotator agreement (IAA), and reviewed before full production begins. Schema ambiguities are resolved at this stage.

Step 4 —

Production with continuous sampling QA

Full-scale annotation with random sampling quality checks throughout. Annotators receive specific feedback on flagged items — not just rejection.

Step 5 —

Independent review and delivery

A separate review team checks a defined percentage of completed annotations. Final dataset delivered with a quality report, IAA scores, and annotation coverage summary.
 

All 22 Indian languages covered as standard

If you are building AI for Indian users, you need annotation in the languages Indian users actually speak — including dialects, code-mixed varieties, and the colloquial registers that general platforms do not cover. We cover all 22 scheduled Indian languages with professional linguist oversight.

Pilot-first approach — no large commitments before quality is confirmed

Every new annotation engagement starts with a pilot batch of 200–500 items. You confirm the schema works, the quality meets your threshold, and the annotators understand your domain before scaling. No large commitments before quality is confirmed.

India-based, India-timezone, 10 years of language data experience

Based in New Delhi and Bhopal. Available in your timezone for project reviews, schema calls, and delivery discussions. No international markup, no coordination overhead.

Native linguists — not crowd workers

Every annotation project is assigned to native-speaking linguists with domain expertise. We do not route projects through a crowd platform. This produces measurably higher inter-annotator agreement, fewer schema violations, and annotation that reflects how language is actually used in the target market.

Why AI Teams Choose
LanguageMark for Annotation

Languages annotated

Indian languages covered

Years of language data experience

Projects available — no minimum commitment
 

Frequently Asked Questions (FAQ)

Q: What is data annotation and why does AI need it?
Data annotation is the process of adding labels, tags, or metadata to raw data — text, audio, images, or video — so that AI and machine learning models can learn from it. Supervised learning models require labeled examples to train on. Without accurately annotated data, a model has no reliable signal to learn from, regardless of how much data it processes. The quality of the annotation directly determines the quality of the model’s output.
The terms are used interchangeably in most contexts. Labeling typically refers to assigning a category or class to an item — for example, labeling an image as “cat” or “dog.” Annotation is a broader term that includes labeling but also covers more complex tasks such as bounding box drawing, NER tagging, sentiment scoring, and relationship extraction. LanguageMark uses both terms to describe the full range of services we provide for AI training data.
Yes. LanguageMark provides data annotation in all 22 officially recognised Indian languages — including Hindi, Bengali, Tamil, Telugu, Marathi, Gujarati, Kannada, Malayalam, Punjabi, Urdu, and all others. We also cover regional dialect variants and code-mixed varieties such as Hinglish. Based in New Delhi and Bhopal, we have been working in Indian languages professionally since 2014.
 
We apply a five-stage quality process: schema design and alignment, annotator selection and calibration, pilot batch with inter-annotator agreement measurement, production annotation with continuous sampling QA, and independent review before delivery. Every delivery includes a quality report with IAA scores and annotation coverage summary. We do not consider quality assurance a final check — it is built into every stage.
We deliver in all standard AI training formats — JSON, JSONL, CSV, CoNLL, BIO, IOB, XML, COCO, and custom schema formats. We work with your existing data pipeline and tooling, including Hugging Face datasets format and proprietary systems. Format requirements are confirmed before work begins and validated at delivery.
Yes — and we recommend it. A pilot of 200–500 annotated items lets you confirm annotation quality, validate the schema, and measure inter-annotator agreement before scaling. Pilots are quoted separately with no obligation to proceed to production. Most of our ongoing clients started with a pilot and moved to a larger engagement after confirming quality.

Data Collection Services

Need raw data before you can annotate? We collect speech recordings, text corpora, and dialogue data across 197+ languages — purpose-built for your model requirements.

MTPE — AI Translation Post-Editing

Human expert review of AI-generated translation output. The same quality-first approach we apply to annotation, applied to language quality assurance.

You May Also Need

Multilingual Data Services Hub

Overview of all our AI data services — annotation, collection, dataset QA, and RLHF data — in one place.

Need Annotation You Can
Trust for Production?

Tell us your annotation schema, target languages, and volume. We will respond within one business day with a proposed approach, quality methodology, and pilot project scope. No minimum commitment to start.
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