Multilingual Universal Part-of-Speech Tagging in Flair (default model)

This is the default multilingual universal part-of-speech tagging model that ships with Flair .

F1-Score: 98,47 (12 UD Treebanks covering English, German, French, Italian, Dutch, Polish, Spanish, Swedish, Danish, Norwegian, Finnish and Czech)

Predicts universal POS tags:

Based on Flair embeddings and LSTM-CRF.

Demo: How to use in Flair

Requires: Flair ( pip install flair )

from flair.data import Sentence
from flair.models import SequenceTagger

# load tagger
tagger = SequenceTagger.load("flair/upos-multi")

# make example sentence
sentence = Sentence("Ich liebe Berlin, as they say. ")

# predict POS tags
tagger.predict(sentence)

# print sentence
print(sentence)

# iterate over tokens and print the predicted POS label
print("The following POS tags are found:")
for token in sentence:
    print(token.get_label("upos"))

This yields the following output:

Token[0]: "Ich" → PRON (0.9999)
Token[1]: "liebe" → VERB (0.9999)
Token[2]: "Berlin" → PROPN (0.9997)
Token[3]: "," → PUNCT (1.0)
Token[4]: "as" → SCONJ (0.9991)
Token[5]: "they" → PRON (0.9998)
Token[6]: "say" → VERB (0.9998)
Token[7]: "." → PUNCT (1.0)

So, the words " Ich " and " they " are labeled as pronouns (PRON), while " liebe " and " say " are labeled as verbs (VERB) in the multilingual sentence " Ich liebe Berlin, as they say ".

Training: Script to train this model

The following Flair script was used to train this model:

from flair.data import MultiCorpus
from flair.datasets import UD_ENGLISH, UD_GERMAN, UD_FRENCH, UD_ITALIAN, UD_POLISH, UD_DUTCH, UD_CZECH, \
    UD_DANISH, UD_SPANISH, UD_SWEDISH, UD_NORWEGIAN, UD_FINNISH
from flair.embeddings import StackedEmbeddings, FlairEmbeddings

# 1. make a multi corpus consisting of 12 UD treebanks (in_memory=False here because this corpus becomes large)
corpus = MultiCorpus([
    UD_ENGLISH(in_memory=False),
    UD_GERMAN(in_memory=False),
    UD_DUTCH(in_memory=False),
    UD_FRENCH(in_memory=False),
    UD_ITALIAN(in_memory=False),
    UD_SPANISH(in_memory=False),
    UD_POLISH(in_memory=False),
    UD_CZECH(in_memory=False),
    UD_DANISH(in_memory=False),
    UD_SWEDISH(in_memory=False),
    UD_NORWEGIAN(in_memory=False),
    UD_FINNISH(in_memory=False),
])

# 2. what tag do we want to predict?
tag_type = 'upos'

# 3. make the tag dictionary from the corpus
tag_dictionary = corpus.make_tag_dictionary(tag_type=tag_type)

# 4. initialize each embedding we use
embedding_types = [

    # contextual string embeddings, forward
    FlairEmbeddings('multi-forward'),

    # contextual string embeddings, backward
    FlairEmbeddings('multi-backward'),
]

# embedding stack consists of Flair and GloVe embeddings
embeddings = StackedEmbeddings(embeddings=embedding_types)

# 5. initialize sequence tagger
from flair.models import SequenceTagger

tagger = SequenceTagger(hidden_size=256,
                        embeddings=embeddings,
                        tag_dictionary=tag_dictionary,
                        tag_type=tag_type,
                        use_crf=False)

# 6. initialize trainer
from flair.trainers import ModelTrainer

trainer = ModelTrainer(tagger, corpus)

# 7. run training
trainer.train('resources/taggers/upos-multi',
              train_with_dev=True,
              max_epochs=150)

Cite

Please cite the following paper when using this model.

@inproceedings{akbik2018coling,
  title={Contextual String Embeddings for Sequence Labeling},
  author={Akbik, Alan and Blythe, Duncan and Vollgraf, Roland},
  booktitle = {{COLING} 2018, 27th International Conference on Computational Linguistics},
  pages     = {1638--1649},
  year      = {2018}
}

Issues?

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