You may have noticed that there are quite a few extra letters in the Arabic language, compared to the basic Semitic alphabet. These are derivatives of the basic letters:
- ذ ð
- خ x
- ظ ẓ/ðˤ
- غ ɣ
- ض ḍ
- ش ʃ
- ث θ
There are quite a few modified Hebrew letters too, but these exist mostly to allow the writing of non-indigenous phones, such as /p/ and /v/. The Semitic alphabet actually fits the Hebrew language much better than the Arabic language, because it was designed to transcribe North-West Semitic languages (i.e. Canaanite, Phoenician) whose modern descendent is Hebrew. Arabic is a Central Semitic language which has retained the above consonants from Proto-Semitic.
Proto-Semitic had 5 triads of voiced/voiceless/emphatic consonants:
- Dental stops: d t tˤ
- Velar stops: g k kˤ (phonetically g k q)
- Interdental: ð θ θˤ
- Dental sibilants: z s/ʃ sˤ
- Lateral: l ɬ ɬˤ (also written l ś śˤ)
As Proto-Semitic evolved into North-Western Semitic, several of these consonant sounds coalesced. The dental stops remained separate (although in modern Hebrew, taw t and teth tˤ are pronounced the same), as did the velar stops. Among the sibilants (dental, interdental and lateral):
- the voiced ð and z coalesced to make zayin z, but l lamed remained separate.
- the unvoiced θ, ʃ and ɬ coalesced to make shin ʃ, but s samekh remained separate.
- the emphatic θˤ, sˤ and ɬˤ coalesced to make sadhe sˤ (modern hebrew pronounced ts).
The case of shin is the only case where Ancient Hebrew and earlier North-Western languages such as Phoenecian where not in alignment. While the Ancient Hebrew script followed the Phoenician example, having only one letter for the coalesced θ, ʃ and ɬ, in the spoken language, θ and ʃ had coalesced to ʃ while ɬ had transformed into s. Later diacritics were invented to mark this difference.
The Central Semitic languages such as Arabic retained all the distinctions of the Proto-Semitic language, except for the loss of samekh. By and large the Arabic sounds are the same as those in Proto-Semitic. Exceptions include:
- ɬ -> ʃ and ʃ -> s (the opposite of Hebrew)
- θˤ -> ðˤ~zˤ
- ɬˤ -> dˤ
The origin of the “extra” fricative letters in Arabic is obscured by the fact that these letters are largely not based on the letters with which the sounds coalesced in North-West Semitic, but on the letters which they most ressemble phonetically, hence:
- ð is spelt ذ, derived from daleth, not zayin (ð -> zayin in Hebrew)
- θ is spelt ث, derived from taw, not shin (θ -> shin in Hebrew)
- ðˤ~zˤ (PS θˤ) is spelt ظ , derived from teth, not sadhe (θˤ -> sadhe in Hebrew)
But the following letters do reflect derivation:
- ʃ (PS ɬ) is spelt ش, derived from shin (Arabic ʃ corresponds to shin in Hebrew)
- dˤ (PS ɬˤ) is spelt ض. , derived from sadhe (Arabic dˤ corresponds to sadhe in Hebrew)
Proto-Semitic also had a voiced and unvoiced pair of velar/uvular and pharyngeal fricatives:
- voiced: ɣ/ʁ, ʕ
- unvoiced: x/χ, ħ
These coalseced on the basis of voicing in North-Western Semitic, but not in Central Semitic.
PS | North-West Semitic | Central Semitic | |
Phoen. | MH | MSA | |
t | t taw | t | t ت |
tˤ | tˤ teth | t | tˤ ط |
d | d daleth | d | d د |
ð z |
z zayin | z | ð ذ from daleth z ز |
l | l lamed | l | l ل |
θ ʃ ɬ |
ʃ shin | ʃ ʃ s |
θ ث from taw s س ʃ ش |
s | s samekh | s | – |
θˤ ʃˤ ɬˤ |
sˤ sadhe | ts | ðˤ~zˤ ظ from teth sˤ ص dˤ ض |
ʕ ɣ/ʁ |
ʕ ayin | ʔ | ʕ ع ɣ غ |
ħ x/χ |
ħ heth | χ | ħ ح x خ |