ص، ز، س share ṣafīr, a sibilant/whistling effect. Ṣād is breathy but elevated and emphatic; zāy is voiced, low and open; sīn is breathy, low and open.
Read صَ، زَ، سَ and listen for what remains shared and what differs. The common hiss is not permission to flatten the three sounds into one.
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Ṣād, zāy and sīn: three whistling letters
Letter-by-Letter Qualities and Distinguishing Features
ص، ز، س share ṣafīr, a sibilant/whistling effect. Ṣād is breathy but elevated and emphatic; zāy is voiced, low and open; sīn is breathy, low and open.
Read صَ، زَ، سَ and listen for what remains shared and what differs. The common hiss is not permission to flatten the three sounds into one.