What (and not who) is BERT?

Artificial Intelligence (AI) has revolutionized various fields of technology, and Natural Language Processing (NLP) is no exception. In the field of NLP, one of the standout developments is the introduction of BERT, or Bidirectional Encoder Representations from Transformers. In this article, we will explore the significance of BERT's introduction and its impact on the world of NLP.

What is BERT?

The groundbreaking paper titled "BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding" was authored by Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova at Google AI Language. BERT's key technical innovation was the introduction of bidirectional training of Transformers, a popular model used in neural network-based machine learning systems. Unlike previous models that trained language representations in a unidirectional manner, BERT is capable of reading entire sequences of tokens at once, allowing it to learn the context of a word based on all of its surroundings—both to the left and right.

BERT's success has also influenced further innovation in the field of NLP. Models like RoBERTa, GPT-3, and T5 have built upon the principles and ideas introduced by BERT, leading to even more advanced NLP systems. BERT's pre-training approach and the ability to fine-tune the model for specific tasks has also enabled transfer learning, allowing for improved performance with less data and resources.

The decision to open-source BERT by Google has democratized access to advanced NLP technology. This has led to innovative applications in various fields and has allowed researchers and practitioners from diverse backgrounds to leverage the power of BERT in their work.

BERT's Key Innovation: Bidirectional Training of Transformers

In unidirectional training, models only consider the left or right context of a word when learning language representations. However, BERT’s bidirectional approach enables the capture of a more comprehensive understanding of language. By considering the entire context, the model gains insights into the relationships and dependencies between words, leading to enhanced language understanding capabilities. It enabled the model to better comprehend complex linguistic structures and nuances, making it more adept at various NLP tasks.

BERT's Impact on NLP Tasks

The versatility of BERT extends beyond these examples, as it has shown remarkable improvements in more than 10 key NLP tasks, such as named entity recognition, document classification, and more. Its ability to capture contextual information and exploit the power of transfer learning has elevated the performance of these tasks to new heights.

Another area where BERT excels is question answering. By considering the context of the entire sentence, rather than relying solely on preceding words, BERT is able to accurately answer questions based on the complete understanding of the text. This has proven particularly useful in applications such as chatbots or information retrieval systems.

BERT has also demonstrated exceptional performance in language inference tasks, analyzing the relationships between words and inferring the logical connections within a sentence.

BERT has revolutionized sentiment analysis, enabling more accurate categorization of emotions expressed in text or conversations. This has proven valuable for businesses monitoring customer feedback or gauging public sentiment towards their brand.

Overall, BERT's impact on NLP tasks has been transformational. Its ability to understand language contexts in a bidirectional manner has greatly enhanced the accuracy and performance of various language processing applications. As a result, BERT has become a cornerstone for developing more advanced NLP models and has inspired researchers and developers worldwide to push the boundaries of language understanding.

Transfer Learning with BERT

BERT's bidirectional understanding allowed it to accurately answer questions based on the context of the entire sentence, rather than relying solely on preceding words. For instance, given the question "Who won the Nobel Prize?" and the sentence "Marie Curie won the Nobel Prize twice," BERT could correctly identify Marie Curie as the answer.

Transfer learning with BERT involved pre-training a language model on a large corpus of data, acquiring a general understanding of language structure and context. This pre-trained model could then be fine-tuned for specific tasks, such as text classification or named entity recognition, resulting in improved performance compared to training models from scratch.

RoBERTa, one of the models built on BERT, achieved state-of-the-art results in various language understanding tasks. For instance, it outperformed previous models in the GLUE benchmark, a collection of diverse NLP tasks, displaying the impact of BERT's foundational concepts.

Open-Sourcing BERT

Google's decision to open-source BERT allowed researchers, developers, and data scientists from around the world to access and utilize this powerful tool. This accessibility facilitated collaborative research, innovation, and the development of applications that benefit society.

The availability of BERT as an open-source tool led to the democratization of NLP technology. This meant that individuals and organizations without significant resources or specialized expertise could harness the power of advanced language models like BERT, driving innovation in various fields like customer service chatbots, content generation, and language translation.

Transfer learning with BERT

One of the most significant advantages of BERT's pre-training approach is its ability to facilitate transfer learning. Transfer learning is the process of utilizing learned knowledge from one task or dataset and applying it to another related task or dataset. BERT's pre-training allows it to acquire a general understanding of language structure and context from a vast amount of data. This pretrained model can then be fine-tuned on specific tasks or datasets, improving performance even with limited labeled data.

By leveraging BERT's pretrained weights and fine-tuning techniques, AI practitioners can expedite the development of NLP models for various applications. Fine-tuning involves adding task-specific layers or training on task-specific datasets to tailor BERT's language understanding capabilities to the specific needs of a task. This transfer learning with BERT serves as a powerful starting point, allowing AI practitioners to build specialized models more efficiently and effectively.

The concept of transfer learning with BERT has opened up new possibilities in NLP research and applications. It enables faster development of accurate and robust NLP models, even in domains with limited labeled data. By building upon BERT's foundational knowledge, researchers and practitioners can push the boundaries of what's possible in AI and NLP, leading to significant advancements in the field.


In conclusion, the introduction of BERT (Bidirectional Encoder Representations from Transformers) has revolutionized the field of NLP by allowing for reading of entire sequences of tokens on both the left and the right, leading to significant improvements in various NLP tasks, including question answering and language inferencing.

Google’s democratization of the tool contributes to the accessibility of BERT by researchers, developers, and data scientists to drive innovation and contribute to the growth and improvement of NLP models.

You can read more about this in the the paper titled "BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding" by Jacob Devlin, Ming-Wei Chang, Kenton Lee, and Kristina Toutanova at Google AI Language laid the groundwork for this influential AI model.