Context: Modern software systems (e.g., Apache Spark) are usually written in multiple programming languages (PLs). There is little understanding on the phenomenon of multi-programming-language commits (MPLCs), which involve modified source files written in multiple PLs. Objective: This work aims to explore MPLCs and their impacts on development difficulty and software quality. Methods: We performed an empirical study on eighteen non-trivial Apache projects with 197,566 commits. Results: (1) the most commonly used PL combination consists of all the four PLs, i.e., C/C++, Java, JavaScript, and Python; (2) 9% of the commits from all the projects are MPLCs, and the proportion of MPLCs in 83% of the projects goes to a relatively stable level; (3) more than 90% of the MPLCs from all the projects involve source files in two PLs; (4) the change complexity of MPLCs is significantly higher than that of non-MPLCs; (5) issues fixed in MPLCs take significantly longer to be resolved than issues fixed in non-MPLCs in 89% of the projects; (6) MPLCs do not show significant effects on issue reopen; (7) source files undergoing MPLCs tend to be more bug-prone; and (8) MPLCs introduce more bugs than non-MPLCs. Conclusions: MPLCs are related to increased development difficulty and decreased software quality.

翻译：背景：现代软件系统（如Apache Spark）通常采用多种编程语言（PL）编写。目前对涉及多种编程语言修改的多编程语言提交（MPLC）现象尚缺乏深入理解。目的：本研究旨在探索MPLC及其对开发难度和软件质量的影响。方法：我们对18个规模较大的Apache项目进行了实证研究，涵盖197,566次提交。结果：（1）最常用的PL组合包含全部四种语言，即C/C++、Java、JavaScript和Python；（2）所有项目中9%的提交属于MPLC，且83%项目中MPLC的比例趋于相对稳定水平；（3）超过90%的MPLC涉及两种PL的源文件；（4）MPLC的变更复杂度显著高于非MPLC；（5）89%的项目中，MPLC修复的问题所需解决时间显著长于非MPLC修复的问题；（6）MPLC对问题重新开启未表现出显著影响；（7）经历MPLC的源文件往往具有更高的缺陷倾向性；（8）MPLC引入的缺陷数量多于非MPLC。结论：MPLC与开发难度增加及软件质量下降密切相关。