Interjections are parts of speech that show emotion. Oh, ouch and wow are examples of common interjections. Many English interjections have sounds that rarely or never occur in other words.
The interjection uh-oh has a glottal stop that occurs between two vowels. This is a relatively unusual sound sequence in English.
In psst, which can be interpreted as here, the entire syllable consists of consonants. This is also the case with shh, which has the meaning of quiet.
The interjection tsk-tsk can also be written as tut-tut. It has a dental click.
In ugh, the final sound is a velar fricative, a sound that is rare in English. The first sound of phew can be a bilabial fricative, also rare in English.
The interjections yeah and uh have vowel sounds that are rarely found in syllable-final position in English. They usually come before a syllable-final consonant.
English interjections have a number of sounds that are rare in English such as velar fricatives and dental clicks. Certain interjections have unusual sound sequences which consist of consonantal syllables and vowels in unusual environments. English interjections have sounds and sound sequences normally not found in other parts of speech.