I want to know what is the relation between the two terms "Stem-Changing Verbs" and "Strong Verbs".

Form what I understand there is a group of verbs that I called "Stem-Changing Verbs" which change their stem in the du and er/sie/es froms in the present tense. b.Z:

• schlafen -> er schläft
• lesen -> er liest

The only patterns for this verbs are:

• a -> ä
• e -> i
• e -> ie

On the other hands, there are "strong verbs" which are divided into these nice ablaut classes that describe the changes which the main vowel of the verb undergoes in the preterite and past participle forms (but not about the change in the present tense)

My questions are:

• Is what I have written so far correct?
• Is every "Stem-Changing Verbs" also a "Strong Verb"?
• If so, can I know from an ablaut class what change will the vowel go through in the present tense?

I want to know what is the relation between the two terms "Stem-Changing Verbs" and "Strong Verbs".

Form what I understand there is a group of verbs that I called "Stem-Changing Verbs" which change their stem in the du and er/sie/es froms in the present tense. b.Z:

• schlafen -> er schläft
• lesen -> er liest

The only patterns for this verbs are:

• a -> ä
• e -> i
• e -> ie

On the other hands, there are "strong verbs" which are divided into these nice ablaut classes that describe the changes which the main vowel of the verb undergoes in the preterite and past participle forms (but not about the change in the present tense)

My questions are:

1. Is what I have written so far correct?
2. Is every "Stem-Changing Verbs" also a "Strong Verb"?
3. If so, can I know from an ablaut class what change will the vowel go through in the present tense?