Emphatic Ra (ر) and Thin Ra (ر) in Arabic
Emphatic Ra (ر):
The emphatic Ra (ر) is always pronounced with a strong exhalation from the back of the throat.
It occurs in the following cases:
1) When Ra is open (مفتوحة) at the beginning of a word:

Example: رَحِيم (Raheem) – Merciful

1) When Ra is open (مفتوحة) in the middle of a word:

Example: بِرَبِّكُم (Bi-rabbikum) – By your Lord

1) When Ra is closed (مضمومة) at the beginning of a word:

Example: رُحْما (Ruhman) – Most Merciful

1) When Ra is closed (مضمومة) in the middle of a word:

Example:

بما تبصِرُون (Bima tubsirun) – With what you see

1) When Ra is quiescent (ساكنة) with an original quiescence and preceded by a closed vowel (ضمة) in the middle of a word:

Example: قُرْآنا (Qur’ana) – The Quran
1) When Ra is quiescent (ساكنة) with an original quiescence at the end of a word:

Example: أن اشكُرْ (An ashkur) – That you thank

1) When Ra is quiescent (ساكنة) with an accidental quiescence and preceded by a long vowel (ألف مدية) in the middle of a word:

Example: الدار (Ad-dar) – The house

1) When Ra is quiescent (ساكنة) with an accidental quiescence and preceded by a long vowel (واو مدية) in the middle of a word:

Example: الشكور (Ash-shokoor) – The Grateful

1) When Ra is quiescent (ساكنة) with an original quiescence and preceded by an open vowel (فتح) in the middle of a word:

Example: مَرْيم (Maryam) – Mary
⦁ Thin Ra (ر):
The thin Ra (ر) is pronounced with a gentle tap of the tongue against the upper alveolar ridge.
It occurs in the following cases:

1) When Ra is closed (مكسورة) at the beginning of a word:

Example: رِزقا (Rizqa) – Provision

1) When Ra is closed (مكسورة) in the middle of a word:

Example: بَرِق (Baraq) – Lightning

1) When Ra is closed (مكسورة) at the end of a word:

Example: بالصّبْرِ عند الوصل (Bal-sabr ‘inda al-wasl) – With patience when connecting

1) When Ra is closed (مكسورة) with an accidental vowel:

Example: وأنذِرِ الناس (Wa-andir an-naas) – And warn the people

1) When Ra is quiescent (ساكنة) with an accidental quiescence due to stopping and preceded by a closed vowel (كسر):

Example: منتشِر (Muntashir) – Widespread

When Ra is quiescent (ساكنة) with an original quiescence at the end of a word and preceded by a closed vowel (كسر) and followed by a rising letter (حرف استعلاء) with an open vowel:

Example:

أن أنذِرْ قَومك (An anzir qawmak) – That you warn your people

1) When Ra is quiescent (ساكنة) and preceded by a closed vowel (كسر) and followed by a rising letter (حرف مستعل) with an open vowel:

Example: ربّ اغفِرْ لِي (Rabb ighfir li) – My Lord, forgive me

1) When Ra is quiescent (ساكنة) and preceded by a closed vowel (كسر) and followed by a non-rising letter (حرف مستفل):

Example: الفِرْدوس (Al-firdaus) – Paradise