Rule to pronounce "i"

[mochaichai]

(1) "i" as in "sino" is pronounced "ai"
(2) "i" as in "Imax" is pronounced as "ai"
(3) "i" as in "Sinomax" (a brand name of pillows) is pronounced as "i"
(4) "i" as in Isabella" is pronounced as "i"

I once heard that if "i" is separated with a vowel by a consonant, such is sino, "i" is pronounced as "ai". However, I cannot see the rule in examples (3) and (4). I wonder if it's because (3) and (4) are names; therefore, it does not apply.

Does anyone know about this? Thank you.

[Casiopea]

I in Imax and i in Sino are diphthongs. That's a vowel made up of two vowel sounds: a+i = ai.

Note, vowels are lax in closed syllables:

(1b) [sai] [no] <diphthong>
(1b) [sIn] [no] <lax vowel; sounds like i in tin>

(2a) [ai] [maeks] <diphthong>
(2b) [Im] [maeks] <lax vowel, tin>

(3a) [sIn] [no] [maeks] <lax vowel; tin>
(3b) [si] [no] [maeks] <tense vowel; sounds like ee in see>

(4a) [Iz] [zae] bella <lax vowel; tin>
(4b) [i] [zae] bella <tense vowel; see>

[mochaichai]

So, are you implying that there is no rule when "i" shall be pronounced as the dipthong /ai/ or the short vowel /i/ (or the long vowel /i:/)? It's really up to our choice?

[Casiopea]

First, "i" is a letter, not a sound. [ai] (as in Hi), [i] (as in me), and [I (as in sit) are sounds that are written using the letter "i".

Second, in English, lax vowels, like [I, occur in closed syllables. So, if you see a word with "i" and it is in a closed syllable, then "i" isn't tense [i] (as in me).

Third, spelling rules tell us that "i" is pronounced [ai] in some words. Often, "e" at the end of a word makes the preceding vowel long. Here are some short vowel words contrasted with vowel words:

bit [I
bite [ai]

hid [I
hide [ai]

dim [I
dime [ai]

grip [I
gripe [ai]

There are more examples here.

Fourth, vowel length is not contrastive in English; it's not phonemic, it's allophonic. Here's what that means. Vowels in the words below are long before voiced sounds and short before voiceless sounds (for most speakers).

beat [i] vs. bead [i:]
seat [i] vs. seed [i:]
leak [i] vs. league [i:]
peace [i] vs. peas [i:]

Source

Hope that helps.

[mochaichai]

Thank you very much for your help.

Just one more quick question. What is the meaning of a "closed syllable"? Is it the same as a consonant?

[Casiopea]

Syllables are made up of consonants (C) and vowels (V). Open syllables look like this, CV, and closed syllables look like this CVC. So, for example,

sit CVC, closed syllable
me CV, open syllable
star CCVC, closed syllable
inch VCC, closed syllable

Hope that helps. Let us know if you have any questions.

[mochaichai]

Thank you, Casiopea. I can understand the meaning of a "closed syllable" from your examples. Thanks again for the good illustration.

[Casiopea]

You're welcome, mochaichai.

[AlainK]

Thank you very much Cassiopea, in tabulae notando.

Er... thrive (vb), jive (n), but live (vb), incentive (n) ?...

I've never found an explanation for the exceptions, well, never mind really, your "VC/VCC" explanation is very practical, merci.

[Buddhaheart]

Er... thrive (vb), jive (n), but live (vb), incentive (n) ?...

"Thrive (vb)" , "jive (n)", "jive (vb)" & "live (n)" are considered to be silent-e or magic-e syllables and there the "i’s" [/aw/ in IPA or /aI/ in SAMPA] are long or diphthongal. The "i" in "live (vb)" is short [ /w/] to distinguish it from its verb counterpart. The "tive" in "incentive (n)" is an exception to the generalization but is consistent in utterance with other words of the same pattern.