Hebrew NLP Toolkit

Instructions

Step 1: Identify the NLP Task

The full ivrit.ai Hebrew audio corpus is over 22,000 hours. Each checkpoint lists its own training data on its model card, and the numbers differ: whisper-large-v3 lists about 5,000 hours, while the turbo-ct2 build lists 295 hours of crowd transcriptions plus 93 hours of professionally transcribed speech from other sources.

Several of these models ship custom code and need trust_remote_code=True (Nemotron, dictabert-joint, dictabert-large-char-menaked, neodictabert-bilingual-embed). That flag runs Python from the model repo on your machine, so read the model card and pin a revision in production.

Step 2: Install, Load and Run

Sentiment (ready to use, no fine-tuning):

from transformers import pipeline

oracle = pipeline('sentiment-analysis', model='dicta-il/dictabert-sentiment')
print(oracle(['אני אוהב את השירות']))

NER (grouped entities):

from transformers import pipeline
from tokenizers.decoders import WordPiece

oracle = pipeline('ner', model='dicta-il/dictabert-ner', aggregation_strategy='simple')
# with aggregation_strategy='simple' the tokenizer needs a decoder, per the model card
oracle.tokenizer.backend_tokenizer.decoder = WordPiece()
print(oracle('דוד בן-גוריון נולד בפולין'))

Without the decoder line, grouped entities come back as broken ## word-piece fragments.

DictaBERT (base model, fill-mask):

from transformers import AutoTokenizer, AutoModelForMaskedLM

tokenizer = AutoTokenizer.from_pretrained("dicta-il/dictabert")
model = AutoModelForMaskedLM.from_pretrained("dicta-il/dictabert")

dicta-il/dictabert is a masked-LM base with NO classification head. Do not load it with AutoModelForSequenceClassification and run inference, that instantiates a randomly-initialised head and returns meaningless predictions. For classification, fine-tune it on labeled data first, or use a ready task-specific model such as dicta-il/dictabert-sentiment or dicta-il/dictabert-ner.

Morphology and prefix segmentation (dictabert-joint):

from transformers import AutoModel, AutoTokenizer

tokenizer = AutoTokenizer.from_pretrained('dicta-il/dictabert-joint')
model = AutoModel.from_pretrained('dicta-il/dictabert-joint', trust_remote_code=True)
model.eval()
print(model.predict(['ובבית הספר למדנו'], tokenizer, output_style='json'))

Sentence embeddings (NeoDictaBERT):

from sentence_transformers import SentenceTransformer

model = SentenceTransformer("dicta-il/neodictabert-bilingual-embed", trust_remote_code=True)
query_embeddings = model.encode_query(["query: מתכון לעוגת שוקולד"])
document_embeddings = model.encode_document(["עוגת שוקולד פשוטה בעשר דקות"])

Keep the query: prefix on queries as the model card shows; dropping it degrades retrieval.

DictaLM 3.0 (generation, 12B instruct):

from transformers import pipeline

generator = pipeline('text-generation', model="dicta-il/DictaLM-3.0-Nemotron-12B-Instruct", trust_remote_code=True)

For serving, the model card recommends vLLM (vllm serve dicta-il/DictaLM-3.0-Nemotron-12B-Instruct --enable-auto-tool-choice --tool-call-parser hermes --trust-remote-code). For the strongest quality, and an Apache-2.0 license, use dicta-il/DictaLM-3.0-24B-Base. For reasoning tasks, use dicta-il/DictaLM-3.0-24B-Thinking, which writes its chain of thought inside an explicit thinking block before the final answer.

ivrit.ai Whisper (speech-to-text, faster-whisper):

import faster_whisper

model = faster_whisper.WhisperModel('ivrit-ai/whisper-large-v3-turbo-ct2')
segs, _ = model.transcribe('media-file', language='he')
print(' '.join(s.text for s in segs))

segs is a generator, so transcription only runs when you iterate it. On CPU pass device="cpu", compute_type="int8"; vad_filter=True skips silence, and word_timestamps=True gives per-word timing for subtitles. To use plain transformers instead, load ivrit-ai/whisper-large-v3 with pipeline("automatic-speech-recognition", ...) and generate_kwargs={"language": "he"}.

Step 3: Hebrew Text Preprocessing

Before feeding text to models:

1. Normalize: Remove extra whitespace, normalize Unicode (NFC)
2. Handle niqqud: Remove diacritics unless specifically needed
3. Handle English: Decide whether to keep, translate, or mark English tokens
4. Tokenization: DictaBERT and AlephBERT tokenizers split words into WordPiece sub-units, not morphemes. If you need real prefix segmentation (for search indexing, counting, lemmas) run dictabert-joint from Step 2

import re
import unicodedata

def preprocess_hebrew(text):
    # Normalize Unicode
    text = unicodedata.normalize('NFC', text)
    # Remove niqqud and cantillation, but keep maqaf U+05BE and other punctuation in the block
    text = re.sub(r'[֑-ׇֽֿׁׂׅׄ]', '', text)
    # Normalize whitespace
    text = re.sub(r'\s+', ' ', text).strip()
    return text

Stripping the whole U+0591 to U+05C7 range is a common bug: it deletes the maqaf and fuses hyphenated words (עולם־גדול becomes עולםגדול).

Step 4: Nikud Restoration (Diacritization)

The preprocessing above removes nikud. The opposite task, adding nikud back to unvocalized text, is called diacritization and is its own core Hebrew NLP problem (useful for text-to-speech, language learning, and disambiguation).

Dicta's Nakdan is the standard tool. The character-level model is published on HuggingFace:

from transformers import AutoModel, AutoTokenizer

tokenizer = AutoTokenizer.from_pretrained('dicta-il/dictabert-large-char-menaked')
model = AutoModel.from_pretrained('dicta-il/dictabert-large-char-menaked', trust_remote_code=True)
model.eval()

# predict takes a list of sentences and returns a list of vocalized sentences
vocalized = model.predict(['שלום עולם'], tokenizer)

Notes:

• trust_remote_code=True is required because the model ships a custom predict head. Review the model card before enabling it.
• The model card says it targets modern Hebrew prose and is not intended for Biblical, Rabbinic, premodern or poetic texts.
• Diacritization is ambiguous: the same consonantal text can have multiple valid vocalizations depending on context. Treat output as a best guess, not ground truth.
• For full sentence-level vocalization with morphological context, Dicta's hosted Nakdan (see Step 5) generally outperforms a raw character model.

Step 5: Hosted Dicta REST APIs

If you do not want to run models locally, Dicta exposes its tools (Nakdan, morphology, and more) as hosted web services. This suits low-volume use, prototyping, or environments without a GPU.

• Nakdan (diacritization): https://nakdan.dicta.org.il/
• Developer access and API details: https://dicta.org.il/developers

Verify the current endpoint shape, request format, rate limits, and terms of use on the developer page before integrating, as hosted API contracts change. Do not assume an endpoint URL or payload schema, consult the official developer docs.

Step 6: Alternative NLP Entry Points

Dicta and ivrit.ai are the primary Hebrew-specific stacks, but two general NLP frameworks also ship Hebrew pipelines:

• HebSpacy (https://github.com/8400TheHealthNetwork/HebSpacy): a spaCy pipeline whose published model, he_ner_news_trf, is an AlephBERT-based NER model with 16 entity types. It does not ship POS tagging or lemmatization. Good when you already use spaCy and need Hebrew NER. Check the repository's last commit date and pin your spaCy version before adopting it.
• Stanza (https://stanfordnlp.github.io/stanza/): Stanford's NLP toolkit ships a Hebrew model with tokenization, morphology, lemmatization, and dependency parsing. Good for academic / cross-lingual pipelines.

For best Hebrew accuracy, Dicta models still lead. Use these frameworks when integration convenience outweighs raw quality.

Step 7: Handle Hebrew-Specific Challenges

• Morphological analysis: Use dictabert-joint (or Dicta's hosted tools) for accurate word segmentation
• No capital letters: Hebrew has no upper/lowercase distinction -- NER is harder
• Right-to-left in code: Ensure proper bidi handling in string operations
• Mixed Hebrew-English: Common in tech text, may need separate processing
• Licenses differ per model: DictaBERT models are CC-BY-4.0, DictaLM 24B is Apache-2.0, the Nemotron 12B variant is under the NVIDIA Open Model License. Check before shipping commercially

Examples

Example 1: Hebrew Text Classification

User says: "I need to classify Hebrew customer reviews as positive or negative" Result: Run dicta-il/dictabert-sentiment through the sentiment-analysis pipeline first (it works without training). Fine-tune it on labeled domain reviews only if its accuracy on a sample of your data is not good enough.

Example 2: Hebrew Named Entity Recognition

User says: "Extract company and person names from Hebrew articles" Result: Use the dicta-il/dictabert-ner pipeline with aggregation_strategy='simple' and the WordPiece decoder, then keep the ORG and PER entities.

Example 3: Transcribe a Hebrew Recording

User says: "Transcribe a one-hour Hebrew podcast to text" Result: Use faster-whisper with ivrit-ai/whisper-large-v3-turbo-ct2, language='he', and vad_filter=True; iterate the segments generator and write each segment's text with its timestamps.

Bundled Resources

Scripts

• scripts/preprocess_hebrew.py: Normalize Hebrew text before feeding it to NLP models (DictaBERT, DictaLM, AlephBERT). Handles Unicode NFC normalization, niqqud removal (keeping the maqaf), whitespace cleanup, URL stripping, thousands-separator and shekel-abbreviation normalization, and mixed Hebrew-English text segmentation. Run: python scripts/preprocess_hebrew.py --help

References

• references/model-comparison.md: Side-by-side comparison of Hebrew NLP models (DictaLM 3.0, DictaBERT, AlephBERT, NeoDictaBERT, ivrit.ai Whisper) with VRAM requirements, HuggingFace IDs, licenses, and a task-to-model mapping table. Consult when choosing which model to use for a specific Hebrew NLP task.

Reference Links

Gotchas

• Hebrew has no capital letters, so agents cannot use capitalization-based NER (Named Entity Recognition) heuristics that work for English. Hebrew NER requires morphological analysis or trained models.
• Hebrew words can be prefixed with multiple particles (prepositions, conjunctions, articles) that are written as part of the word. The string "ובבית" (u-va-bayit) is "and in the house" as a single token. Agents may treat it as one word.
• The Hebrew letter system has five final forms (sofit): kaf, mem, nun, pe, tsadi. Agents may normalize these to their non-final forms, breaking word matching and search.
• Nikud (vowel diacritics) is almost never present in modern Hebrew text. Agents trained on nikud-annotated text may fail on standard unvocalized Hebrew. Always design for nikud-less input.
• Agents often "normalize" the shekel abbreviation with a plain substring replace of ש and ח, which also rewrites ordinary words such as שחר and משחק. Match it only as a standalone token.

Troubleshooting

Error: "Tokens look like fragments with ## in them"

Cause: DictaBERT and AlephBERT use WordPiece tokenization, which splits rare words into sub-word pieces. These are not morphemes. Solution: For NER, set aggregation_strategy='simple' plus the WordPiece decoder shown in Step 2. For real prefix segmentation, use dictabert-joint.

Error: "GPU out of memory"

Cause: in BF16 the weights alone take about 2 bytes per parameter, so roughly 48GB for DictaLM 3.0 24B and roughly 24GB for the Nemotron-12B variant, before KV cache and activations. Solution: Drop to dicta-il/DictaLM-3.0-Nemotron-12B-Instruct (12B), the 1.7B Thinking GGUF variant, or use the FP8 / W4A16 quantized checkpoints published under the same org (e.g., DictaLM-3.0-24B-Base-FP8). For laptop-class hardware, run a GGUF build via llama.cpp.