TswanaBert

Pretrained model on the Tswana language using a masked language modeling (MLM) objective.

Model Description.

TswanaBERT is a transformer model pre-trained on a corpus of Setswana in a self-supervised fashion by masking part of the input words and training to predict the masks by using byte-level tokens.

Intended uses & limitations

The model can be used for either masked language modeling or next-word prediction. It can also be fine-tuned on a specific downstream NLP application.

How to use

>>> from transformers import pipeline
>>> from transformers import AutoTokenizer, AutoModelWithLMHead

>>> tokenizer = AutoTokenizer.from_pretrained("MoseliMotsoehli/TswanaBert")
>>> model = AutoModelWithLMHead.from_pretrained("MoseliMotsoehli/TswanaBert")
>>> unmasker = pipeline('fill-mask', model=model, tokenizer=tokenizer)
>>> unmasker("Ntshopotse <mask> e godile.")

[{'score': 0.32749542593955994,
  'sequence': '<s>Ntshopotse setse e godile.</s>',
  'token': 538,
  'token_str': 'Ġsetse'},
 {'score': 0.060260992497205734,
  'sequence': '<s>Ntshopotse le e godile.</s>',
  'token': 270,
  'token_str': 'Ġle'},
 {'score': 0.058460816740989685,
  'sequence': '<s>Ntshopotse bone e godile.</s>',
  'token': 364,
  'token_str': 'Ġbone'},
 {'score': 0.05694682151079178,
  'sequence': '<s>Ntshopotse ga e godile.</s>',
  'token': 298,
  'token_str': 'Ġga'},
 {'score': 0.0565204992890358,
  'sequence': '<s>Ntshopotse, e godile.</s>',
  'token': 16,
  'token_str': ','}]

Limitations and bias

The model is trained on a relatively small collection of sestwana, mostly from news articles and creative writings, and so is not representative enough of the language as yet.

Training data

The largest portion of this dataset (10k) sentences of text, comes from the Leipzig Corpora Collection
We then added SABC news headlines collected by Marivate Vukosi, & Sefara Tshephisho, (2020) that are generously made available on zenoodo. This added 185 tswana sentences to my corpus.
We went on to add 300 more sentences by scrapping following news sites and blogs that mostly originate in Botswana. We actively continue to expand the dataset.

http://setswana.blogspot.com/
https://omniglot.com/writing/tswana.php
http://www.dailynews.gov.bw/
http://www.mmegi.bw/index.php
https://tsena.co.bw
http://www.botswana.co.za/Cultural_Issues-travel/botswana-country-guide-en-route.html
https://www.poemhunter.com/poem/2013-setswana/ https://www.poemhunter.com/poem/ngwana-wa-mosetsana/

BibTeX entry and citation info

@inproceedings{author = {Moseli Motsoehli},
  year={2020}
}