Enhancing Code Generation for Low-Resource Languages: No Silver Bullet
Authors: name: Alessandro Giagnorio, name: Alberto Martin-Lopez, name: Gabriele Bavota

The advent of Large Language Models (LLMs) has significantly advanced the
field of automated code generation. LLMs rely on large and diverse datasets to
learn syntax, semantics, and usage patterns of programming languages. For
low-resource languages (i.e., niche programming languages characterized by the
scarcity of training data), the limited availability of such data hampers the
models' ability to generalize effectively, resulting in poorer code generation
performance as compared to high-resource languages. For this reason, there is a
quest for techniques able to close this performance gap. We present an
empirical study investigating the effectiveness of several approaches for
boosting LLMs' performance on low-resource languages, namely: (i) a classic
fine-tuning, which is however capped in size by the scarcity of training data;
(ii) three variants of in-context learning, with prompts crafted to provide the
LLM with additional information about the low-resource language (e.g., few-shot
examples showcasing features of the targeted language); and (iii) a
pre-training objective teaching the model how to translate between high- and
low-resource languages. The context of our study are two low-resource languages
(R and Racket) and six LLMs having different architectures and sizes. Our
findings reveal that a fine-tuning is usually the best choice for smaller LLMs,
possibly due to the fact that even a small dataset is sufficient to train their
limited number of parameters. With the increase in size of the models,
in-context learning becomes more and more effective, representing a safe and
cheap bet (i.e., it always helps, but with different magnitudes). Differently,
very large LLMs may deteriorate their performance on low-resource languages
when fine-tuning is performed, possibly due to the lack of enough data needed
to effectively update their weights.