Sample-Ngomba-TTS-Dataset

Language

Ngomba (ISO 639-3: jgo) is a Grassfields Bantu language belonging to the Niger-Congo phylum, classified within the Mbam-Nkam branch. It is spoken in the Bamboutos Division of the West Region of Cameroon, where it belongs to the Central-Bamileke cluster alongside Mengaka, Ngombale, and Ngiemboon (Breton & Bikia Fohtung 1991). Despite its sociolinguistic significance within the Bamileke cultural area of Cameroon, Ngomba remains substantially underrepresented in language technology resources.

Variants

According to the Administrative Atlas of Cameroon's Languages (Breton & Bikia Fohtung 1991), Ngomba comprises the following dialects:

• Bameso

• Bamendjinda

• Bamete

Writing System

The writing system used for the transcription of Ngomba in this dataset is the General Alphabet of Cameroon's Languages (AGLC). The AGLC provides a phonologically motivated orthographic standard for Cameroonian national languages and serves as the reference framework for Ngomba literacy materials.

1. Vowels

The vowel system attested in the dataset includes the following oral vowels:

a, e, i, o, u, ɛ, ɔ, ʉ, ʉ̈

Where:

• ɛ (epsilon): open-mid front unrounded vowel

• ɔ (open-o): open-mid back rounded vowel

• ʉ (barred u): high central rounded vowel

• ʉ̈ (barred u with diaeresis): a distinct Ngomba vowel grapheme, frequently appearing in the sequence ʉ̈ɔ and in standalone position (e.g., kʉ̈, cʉ̈, pʉ̈)

Long vowels are represented by vowel doubling (e.g., aa, ɛɛ, ɔɔ, uu, ʉʉ).

2. Consonants

The consonant inventory reflected in the dataset includes simple, digraph, and labialized consonants:

b, c, d, f, g, h, j, k, l, m, n, p, s, sh, t, v, w, y, z, ŋ

Labialized consonants are formed by appending ẅ (w with diaeresis, U+1E85) to the base consonant or cluster:

• gẅ: labialized voiced velar stop

• sẅ: labialized alveolar fricative

• cẅ: labialized palatal affricate

• kẅ: labialized velar stop

• tsẅ: labialized alveolar affricate

Special symbols:

• ŋ (eng, U+014B): velar nasal consonant

• sh: voiceless postalveolar fricative

• ẅ (w with diaeresis, U+1E85): labialization marker, appended to consonants

• ꞌ (Latin small letter saltillo, U+A78C): glottal stop / glottal closure marker

3. Syllabic nasals

Ngomba attests syllabic nasal consonants that function as tone-bearing units. The following tone-marked syllabic nasals are represented in the dataset:

• ḿ (m with acute): syllabic bilabial nasal, high tone

• ń (n with acute): syllabic alveolar/palatal nasal onset, high tone

• ǹ (n with grave): syllabic alveolar nasal, low tone

• ŋ́ (eng with acute): velar nasal onset, high tone

4. Tone system

Ngomba is a tonal language with multiple contrastive pitch levels and contour tones. The dataset employs systematic tone marking on vowels and syllabic nasals in accordance with the AGLC convention. The following diacritics are attested in the dataset:

Level tones:

• High tone (H): acute accent — á, é, í, ó, ú, ɛ́, ɔ́, ʉ́

• Low tone (L): grave accent — à, è, ì, ò, ù, ɛ̀, ɔ̀, ʉ̀

Contour tones:

• Falling tone (HL): circumflex — â, ê, î, ô, û, ɛ̂, ɔ̂, ʉ̂

• Rising tone (LH): caron — ǎ, ě, ǐ, ǒ, ǔ, ɛ̌, ɔ̌, ʉ̌

Mid tone is generally left unmarked in the Ngomba AGLC orthography.

Source

The dataset was compiled from scripted speech prompt lists read by a native speaker. Sentences were selected to provide broad phonological coverage of Ngomba and were transcribed in accordance with the AGLC orthographic standard.

Domain

The dataset represents scripted speech in Ngomba, covering a broad range of everyday sentence types drawn from a general-purpose TTS/ASR prompt list. All utterances are scripted rather than spontaneous.

Size

Total audio duration: 3,978 seconds (01h 06m 18s), distributed across 1033 audio clips in 11 recording sessions.

Structure

The dataset is organised into 11 recording sessions:

• Session tts_dataset_jgo_01: 100 clips (08m 04s)

• Session tts_dataset_jgo_02: 100 clips (07m 18s)

• Session tts_dataset_jgo_03: 100 clips (08m 13s)

• Session tts_dataset_jgo_04: 100 clips (08m 01s)

• Session tts_dataset_jgo_05: 99 clips (06m 19s)

• Session tts_dataset_jgo_06: 100 clips (05m 54s)

• Session tts_dataset_jgo_07: 100 clips (05m 39s)

• Session tts_dataset_jgo_08: 100 clips (05m 35s)

• Session tts_dataset_jgo_09: 100 clips (04m 44s)

• Session tts_dataset_jgo_10: 100 clips (04m 34s)

• Session tts_dataset_jgo_11: 34 clips (01m 51s)

Each session folder contains:

1. Audio clips (MP3 format; session 07 additionally contains 2 WAV files)

2. One per-session sentence-to-audio mapping file (mapping.tsv), with 4 columns

Description of columns (mapping.tsv)

• #audio_filename: filename of the audio clip (MP3 or WAV)

• #key: unique hash identifier of the recording

• #sentence: sentence text as read by the speaker, transcribed in AGLC orthography

• #attempts: number of recording attempts before acceptance

Sample