Adjective Suffixes – Are -al and -ar the Same Adjective Suffixes?
adjectivesgrammarmorphologysuffixes
This picture is about specific examples of these two suffixes.
Best Answer
Dictionary.com offers a good explanation
-al: a suffix with the general sense “of the kind of, pertaining to, having the form or character of” that named by the stem, occurring in loanwords from Latin ( autumnal; natural; pastoral ), and productive in English on the Latin model, usually with bases of Latin origin ( accidental; seasonal; tribal ). Originally, -al 1 was restricted to stems not containing an -l- (cf. -ar1); recent lapses in this rule have produced semantically distinct pairs, as familiar and familial.
https://www.dictionary.com/browse/-al
In brief: we usually use -al, but when a word ends with an "L" sound, we use -ar. I suppose that's because some people (Latin people, perhaps) found it uncomfortable to pronounce words like "modulal", "tablal" or "titlal."
Note: dictionaries mark the -al suffix as "productive" (meaning that you can produce new words by joining the -al suffix to a noun), but like most things in English, its usage is not consistent.
Usage notes
If the root word contains l, the variant -ar is often used instead (e.g. solar, lunar, columnar, lumbar). Sometimes both forms are found: linear, lineal. One also sees -ial, as in manorial.
As nominalizer, some verbs have two corresponding nouns, one ending in -al and the other in -tion/-sion (more common suffix), with one or the other being more common, sometimes with different nuances. Notable examples: disposition/disposal (dispose), proposition/proposal (propose), submission/submittal (submit), transmission/transmittal (transmit). Some superficial pairs are actually of different origin, notably reversion/reversal (revert/reverse, not both from reverse). https://en.wiktionary.org/wiki/-al
In both American and British English, there is an emphasis on the first O, but not too much. For example, "astronomy" is pronounced:
"as" like "us" (or sometimes "ass" from "class")
"tr" from "trim"
"on" from "marathon"
"om" like "um"
"y" like "ee" from "tree", but shorter
However, in Indian English, I have heard many people pronouncing it astrOHnomy, basically giving the O in "astro" the same emphasis as the O in "micro" and tacking on the "nomy" (rhymes with "mommy"). This is completely different from the pronunciation above, and is wrong in American/British English.
As I commented, I don't have an answer for your question #2. But I can help you with your question #1. The resources you were trying to access and can't seems to redirect to Fowler's Modern English Usage page. Even I don't have access to that page, but I have an image of that page from that book. Here is that page. Please have a look -
Best Answer
Dictionary.com offers a good explanation
In brief: we usually use -al, but when a word ends with an "L" sound, we use -ar. I suppose that's because some people (Latin people, perhaps) found it uncomfortable to pronounce words like "modulal", "tablal" or "titlal."
Note: dictionaries mark the -al suffix as "productive" (meaning that you can produce new words by joining the -al suffix to a noun), but like most things in English, its usage is not consistent.