⟨rd⟩ is used in the transcription of Australian Aboriginal languages such as Warlpiri, Arrernte, and Pitjantjatjara for a retroflex stop, /ʈ/.
⟨rh⟩ is found in English language with words from the Greek language and transliterated through the Latin language. Examples include "rhapsody", "rhetoric" and "rhythm". These were pronounced in Ancient Greek with a voiceless "r" sound, as in Old English ⟨hr⟩. The digraph may also be found within words, but always at the start of a word component, e.g., "polyrhythmic". German, French, and the auxiliary language Interlingua use rh in the same way. ⟨Rh⟩ is also found in the Welsh language where it represents a voiceless alveolar trill (r̥), that is a voiceless "r" sound. It can be found anywhere; the most common occurrence in the English language from Welsh is in the slightly respelled given name "Rhonda". In Wade-Giles transliteration, ⟨rh⟩ is used for the syllable-final rhotic of Mandarin Chinese. In the Gwoyeu Romatzyh romanization of Mandarin Chinese, initial rh- indicates an even tone on a syllable beginning in /ʐ/, which is otherwise spelled r-. In Purépecha, it's a retroflex flap, .
⟨rl⟩ is used in the transcription of Australian Aboriginal languages such as Warlpiri, Arrernte, and Pitjantjatjara for a retroflex lateral, written /ɭ/ in the IPA. In the Greenlandic language, it represents as the result of an assimilation of a consonant cluster with a uvular consonant as the first component.
⟨rm⟩ is used in Inuktitut for .
⟨rn⟩ represents the retroflex nasal /ɳ/ in Warlpiri, Arrernte, and Pitjantjatjara (see transcription of Australian Aboriginal languages). In the Greenlandic language, it represents /ɴ/. In Inuktitut, it represents .
⟨rp⟩ is used in the Greenlandic language for as the result of an assimilation of a consonant cluster with a uvular consonant as the first component.
⟨rr⟩ is used in English language for ⟨r⟩, depending on etymology. It normally appears in words of Latin or Romance origin, and "rrh" in words of ancient Greek origin. It is quite a common digraph, found in words as diverse as arrest, carry, and sorry. Some words with "rr" are relatively recent loanwords from other languages; examples include burro from Spanish. It is often used in impromptu pronunciation guides to denote either an alveolar tap or an alveolar trill. It is a letter in the Albanian alphabet.
In several European languages, such as Catalan, Spanish, Portuguese or Albanian, "rr" represents the alveolar trill /r/ (or the voiced uvular fricative /ʁ/ in Portuguese) and contrasts with the single "r", which represents the alveolar tap /ɾ/ (in Catalan and Spanish a single "r" also represents the alveolar trill at the beginning of words or syllables). In Italian, "rr" is furthermore a geminate (long) consonant /rː/. In Central Alaskan Yup'ik it is used for /χ/.
⟨rs⟩ was equivalent to ⟨rz⟩ and stood for /r̝/ (modern ř) in medieval Czech. In the Greenlandic language, it represents as the result of an assimilation of a consonant cluster with a uvular consonant as the first component.
⟨rt⟩ is used for Australian Aboriginal languages such as Warlpiri, Arrernte, and Pitjantjatjara for a retroflex stop /ʈ/.
⟨rw⟩ is used for /ɻʷ/ in Arrernte.
⟨rz⟩ is used in Polish and Kashubian for a voiced retroflex fricative ʐ, similar to English "zh" as in Zhivago. Examples from Polish are marzec "March" and rzeka "river". ⟨Rz⟩ represents the same sound as ⟨ż⟩, the only difference being that ⟨ż⟩ evolved from a *g while ⟨rz⟩ is descended from a palatalized ar ( *rʲ ). ⟨Rz⟩ usually corresponds to Czech ⟨ř⟩, though the pronunciations are different. When preceded by a voiceless consonant (ch, k, p, t) or end of a word, ⟨rz⟩ devoices to ⟨sz⟩, as in przed "before", pronounced .
Read more about this topic: List Of Digraphs In Latin Alphabets