The primary challenges associated with controlling language proficiency levels in texts generated by large language models (LLMs) include:
Addressing these challenges is crucial for enhancing applications in education and language learning, and making advanced AI tools more accessible to a broader audience.
Current methods such as few-shot prompting, supervised finetuning, and reinforcement learning (RL) attempt to tackle the challenge of controlling the language proficiency levels in texts generated by large language models (LLMs).
Few-shot prompting involves providing the model with a few examples to guide its output. By giving the model a limited number of examples, it can learn to generate text that follows the desired proficiency level. However, few-shot prompting with open-source models often results in high computational costs and suboptimal performance.
Supervised finetuning adjusts the model using a labeled dataset. In this approach, the model is trained on a dataset where each example is labeled with the corresponding proficiency level. This allows the model to learn to generate text that aligns with the desired proficiency levels. However, supervised finetuning requires extensive labeled data, which may not be readily available.
RL, specifically Proximal Policy Optimization (PPO), further refines the model's outputs based on a reward system. The model is trained to maximize a reward signal that encourages generating text aligned with the desired proficiency level. This approach can be effective in controlling the proficiency level, but RL techniques can be unstable and computationally intensive, making them less practical for large-scale applications.
While these methods have shown some success in addressing the challenge of controlling language proficiency levels in generated texts, they have limitations and may not be sufficient for achieving accurate and reliable proficiency control.
The CEFR-Aligned Language Model (CALM) is a novel approach developed by researchers from Stanford and Duolingo to control the language proficiency levels in texts generated by large language models (LLMs). It addresses the limitations of existing methods, such as few-shot prompting, supervised finetuning, and reinforcement learning (RL), by combining finetuning and RL techniques to align the output proficiency levels with the Common European Framework of Reference for Languages (CEFR) standards1.
CALM overcomes the limitations by:
This combination of techniques allows CALM to generate high-quality, proficiency-controlled content at a fraction of the cost of using proprietary models like GPT-4, making it a more accessible and cost-effective solution for applications in education, language learning, and other contexts where users may not be fully proficient in the target language1.