rt & rd

The insertion of [ʃ] between r and a following t, in stressed syllables, is related to pre-aspiration. In some dialects, an [ʃ] is also inserted between r and d. Listen carefully to the following examples:

rt	[kʲaRʃd]	ceart	correct (adj.)
	[ɔRʃd]	ort	on you
	[pɔRʃd]	port	tune (n.)
rd	[aːRʃd]	àrd	high
	[bɔːRʃd]	bòrd	table (n.)
	[ɔːRʃd]	òrd	hammer (n.)

Some speakers pronounce rd groups without inserting an [ʃ]. Listen to the examples without an [ʃ].

rd	[aːRd]	àrd	high
	[bɔːRd]	bòrd	table (n.)
	[ɔːRd]	òrd	hammer (n.)