N4 (NATO Native and Non Native) database

Speech technology is covering an increasing number of languages, and systems are becoming more robust with regard to speech variability such as speaking style and accents. However, for real applications, especially in a multilingual and multinational context, further robustness to regional and even non-native accents is necessary. Among numerous corpora available for speech research few have specifically addressed this issue. The NATO Speech and Language Technology group decided to create a corpus geared towards the study of non-native accents. The group chose naval communications as the common task because it naturally includes a great deal of non-native speech and because there were training facilities where data could be collected in several countries. The N4 NATO Native and Non-Native Speech corpus was developed by the NATO research group on Speech and Language Technology in order to provide a military-oriented database for multilingual and non-native speech processing studies. Speech data was recorded in the naval transmission training centers of four countries (Germany, The Netherlands, United Kingdom, and Canada) during naval communication training sessions in 2000-2002. The material consists of native and non-native speakers using NATO Naval English procedure between ships where the typical sentence sounds like “This is alpha, whiskey, roger. I make two seven zero six hostile, two seven zero six. Out”, and reading from a text, "The North Wind and the Sun," in both English and the speaker's native language. The audio material was recorded on DAT and downsampled to 16kHz-16bit, and all the audio files have been manually transcribed and annotated with speakers identities using the Transcriber tool. Navy procedure recordings and text readings have been stored in different files. The first digit in the filename indicates the type of speech. Among speech segments, the duration of Navy procedure recordings range from 1.3 to 2.3 hours for a total of 7.5 hours. The duration of the native language text readings range from 1.5 minutes to 22.9 minutes for a total of around one hour. <table border="0" width="100%" cellspacing="0" cellpadding="2" class="infoBoxContents"><tr align=center><td></td><td>Canada</td><td>Germany</td><td>The Netherlands</td><td>United Kingdom</td><td>All</td></tr><tr align=center><td align=left><strong>Signal</strong></td><td>5.30</td><td>3.20</td><td>5.00</td><td>6.30</td><td>19.80</td></tr><tr align=center><td align=right>Silence</td><td>3.00</td><td>0.56</td><td>2.00</td><td>4.70</td></tr><tr align=center><td align=right>Speech</td><td>2.30</td><td>2.64</td><td>3.00</td><td>1.60</td></tr><tr align=center><td align=left><strong>Speech</strong></td><td>2.30</td><td>2.64</td><td>3.00</td><td>1.60</td><td>9.54</td></tr><tr align=center><td align=right>Navy proc</td><td>2.00</td><td>1.90</td><td>2.30</td><td>1.30</td></tr><tr align=center><td align=right>Read text</td><td>0.30</td><td>0.74</td><td>0.70</td><td>0...

语音技术正逐渐覆盖越来越多的语言，系统在应对语音变异性方面，如口音和说话风格，正变得更加稳健。然而，对于实际应用而言，尤其是在多语言和多国家的环境中，对地域甚至非母语口音的稳健性需求更为迫切。在众多可供语音研究使用的语料库中，鲜有针对此问题的专门探讨。北约语音与语言技术小组决定创建一个旨在研究非母语口音的语料库。该小组选择海军通信作为共同任务，因为这自然地包含大量的非母语语音，并且存在多个国家能够进行数据收集的训练设施。N4北约母语与非母语语音语料库由北约语音与语言技术研究小组开发，旨在为多语言和非母语语音处理研究提供军事导向的数据库。语音数据于2000年至2002年在四个国家的海军传输训练中心（德国、荷兰、英国和加拿大）的海军通信训练期间进行录制。该材料包括使用北约海军英语程序在舰船间交流的母语和非母语说话者，其典型句子如“这是阿尔法，威士忌，收到。我报告敌情，两七零六，两七零六。完毕”，以及朗读文本《北风与太阳》，包括英语和说话者的母语。音频材料以DAT格式录制，并降采样至16kHz-16bit，所有音频文件均经人工转录，并使用Transcriber工具标注说话者身份。海军程序录音和文本朗读存储在不同的文件中。文件名中的第一个数字表示语音类型。在语音片段中，海军程序录音的时长从1.3至2.3小时不等，总计7.5小时。母语文本朗读的时长从1.5分钟至22.9分钟不等，总计约一小时。