and completely become and respectively in some other particular dialects. Unstressed final long are most often shortened or reduced: → , → , → . However, the actual rules governing vowel-retraction are a good deal more complex and have relatively little in the way of an agreed-upon standard, as there are often competing notions of what constitutes a "prestige" form. Often, even highly proficient speakers will import the vowel-retraction rules from their native dialects. Thus, for example, in the Arabic of someone from Cairo, emphatic consonants will affect every vowel between word boundaries, whereas certain Saudi speakers exhibit emphasis only on the vowels adjacent to an emphatic consonant. Certain speakers (most notably Levantine speakers) exhibit a degree of asymmetry in leftward vs. rightward spread of vowel-retraction. The final heavy syllable of a root is stressed. The short vowels are all possible allophones of across different dialects; e.g., ('I said') is pronounced or or , since the difference between the short mid vowels and is never phonemic, and they are mostly found in complementary distribution, except for a number of speakers where they can be phonemic but only in foreign words. The short vowels are all possible allophones of across different dialects; e.g., ('from') is pronounced or or since the difference between the short mid vowels and is never phonemic, and they are mostly found in complementary distribution, except for a number of speakers where they can be phonemic but only in foreign words. The long mid vowels and appear to be phonemic in most varieties of Arabic except in general Maghrebi Arabic, where they merge with and . For example, لون ('color') is generally pronounced in Mashriqi dialects but in most Maghrebi Arabic. The long mid vowels can be used in Modern Standard Arabic in dialectal words or in some stable loanwords or foreign names, as in ('Rome') and ('cheque'). Foreign words often have a liberal sprinkling of long vowels, as their word shapes do not conform to standardized prescriptive pronunciations written by letters for short vowels. The long mid vowels and are always rendered with the letters and , respectively. In general, the pronunciation of loanwords is highly dependent on the speaker's native variety. Consonants Even in the most formal of conventions, pronunciation depends upon a speaker's background. Nevertheless, the number and phonetic character of most of the 28 consonants has a broad degree of regularity among Arabic-speaking regions.