This article discusses the phonological system of the Czech language. The following chart shows a complete list of the consonant phonemes of Czech: Phonetic notes: Sibilants /ʃ ʒ t͡ʃ d͡ʒ/ are laminal post-alveolars (usually not considered retroflex). The approximant /l/ is mainly pronounced apico-alveolar, although a velarized pronunciation without a firm tongue tip contact is not unusual. Both /r/ and /r̝/ are trills though commonly realized with a single contact. The phoneme r̝, written , is a raised alveolar non-sonorant trill. Its rarity makes it difficult to produce for most foreign learners of Czech, who may pronounce it as [rʒ]; however, it contrasts with /rʒ/ in words like ržát [rʒaːt] ('to neigh'), which is pronounced differently from řád [r̝aːt] ('order'). The basic realization of this phoneme is voiced, but it is voiceless [r̝̊] when preceded or followed by a voiceless consonant or at the end of a word. Phonetically, the sound /r̝/ is a period of friction interrupted at the beginning by a contact or contacts created by a retracted apico-alveolar gesture. Sonorants /r/, /l/ become syllabic between two consonants or after a consonant at the end of a word. /t/ and /d/ can be pronounced as dental stops. While /d/ is commonly realized as apico-alveolar, /t/ is more likely to be laminal denti-alveolar. /c/ and /ɟ/ are alveolo-palatal with primarily lamino-alveolar/postalveolar and lateral dorso-palatal contact. /ɲ/ is alveolo-palatal nasal. The voiceless realization of the phoneme /ɦ/ is velar [x]. The glottal stop is not a separate phoneme. Its use is optional and it may appear as the onset of an otherwise vowel-initial syllable. The pronunciation with or without the glottal stop does not affect the meaning and is not distinctive. The glottal stop has two functions in Czech: The emphasis on the boundaries between words or in compound words is usually inserted between two vowels which do not form a diphthong, e.g. používat [poʔuʒiːvat] ('to use'), táta a máma [taːta ʔa maːma] ('dad and mum'); it separates prepositions from words beginning with a vowel, e.