Definition of regular conjugateable verb is that it is not an irregular verb but is there some spelling rules to decide that verb is regular for students until they memorise all the irregular verbs?Note not the conjugation how to know that it is a regular verb by its spelling.
Unfortunately, I don't think there are any rules like this that would be helpful to know.
There isn't any failproof way to determine whether a verb is regular or irregular if you only know the spelling of its plain form:
There are some pairs of verbs (with different meanings) that have the exact same spelling in the plain form but that conjugate differently in the past tense/past participle: for example, "wind, wound" (a clock) vs. "wind, winded" (a horn).
There are also some verbs in English that can be conjugated either way: for example, the past tense of "dream" can be "dreamed" or "dreamt".
In addition to being incomplete, any rules that you try to teach will be fairly complicated, as there are a number of different types of irregular verbs in English. I would recommend just teaching the verbs as they come up rather than trying to teach rules beforehand. There are definitely patterns in the forms of irregular verbs, but I think students will learn these patterns more effectively from encountering concrete examples rather than from trying to memorize abstract spelling-based rules like "if a verb is spelled with 'zz', it is regular" (which is true, as far as I know, but I don't think it's a useful rule).
Here are some tips to clearly identify regular verbs but they are not without their drawbacks too.
If the verb is derived from Greek, it will be regular. However, very few English verbs have Greek origins. Note that words ending with -ize are usually spelled -ise in British English.
apologis/ze, baptize, cauterize, doctor (yes, it's also a verb), emphasize, hypothesize, idolize, ostracize, program/programme, photograph, synchronize, sympathize, televise, telephone, phone
Exception: the verb ‘panic’ (panikos) is written ‘panicked’ in the Simple Past.
As far as I'm aware, if the verb is derived from Latin, it will be regular, there are too many to list but this should give the OP an idea
act, adapt, coincide, confuse, contain, count, create, debate, decide, delete, decrease, discover, document, enjoy, entertain, emigrate, exercise, explain, fantasize, fund, found 2, generate, inherit, interrupt, invade, invent, judge, maintain, mix, neglect, object, obtain, prepare, produce, progress, prohibit, reject, respond, remix, select, submit, value, volunteer.
If a verb has one of the following forms then it is definitely regular: * ends with "iate" e.g appreciate * Four or longer letter word ends with consonant then "y" is regular e.g. satisfy.