In Arabic usually we use (بدل) as (instead of) I will make some Examples that help you I use car (instead of*) buses * instead of here have the meaning بدل I (replaced*) the use of the bus by using the car *replaced here have the meaning استبدل I hope I answer your qoustion

استبدل means (to replace). For example: استبدلَ بثوبه القديم ثوباً جديداً = He LEFT the old clothes, and TOOK the new one. Which means he replaced his old clothes with new. بدل means (to switch with). For example: بَدَّل الجديد بالقديم = Switch the new with old. PS: we attach ب with the first object after استبدل/ بدل to indicate the object we LEFT Check this website for more information: http://www.reefnet.gov.sy/Arabic_Proficiency/50.htm

The problem with Arabic is that the Arabs themselves still rely on the old studies of grammers. http://www.islamguiden.com/arabi/m_a_r_7.htm we need to refine all this, we need people who make lists of the verb and how the are categorized in new programmed way, I have tried myself and find it very large proccess.

Hi. بدل does not mean change, for /chnge/ we have غيّر بدل means repalce. as for verbs that are enriched with ســ they are convey more information about the action. استبدل means seeek or look for replacing, i.e the action has took place after some efforts. but we have kind of settlment with بدل , it took place without delay(ing). the subject of those verbs that are enriched /we say sweetened in Arabic/ with ســ we have some types. some make the verb in the meaning of /seek or look for/, some other in the meaning of graduating. I have an idea but i could not find one complete text on the subject, I can give some more examples to enlight the idea. we have غفر which means to forgive. but استغفر means seeks or ask for fogivness for oneself. graduation: أخرج to take out of .... استخرج worked on taking out something out of something else. thats why we say استخراج النفط not اخراج النفط here we are highliting the process of gradauting. we have also times when ســ serves as " he deals with a thing as ....". this nothion can be seen in استخدم maked a thing or a person / or deal with/ as خادم we also have استعمل ..which literaly means make a person or a thing as عامل !!! Normaly Arabs nowdays need not to dig deep in this understanding or language but to answer your question the precise way I need to go by all this details. Now be patient and soon you will /feel/ how this varity of Arabic verbs is useful . all the talk in one word is that ســ is a phoneme added to some verbs but notice ot all ســ are phonems , some are from the stem of the verb. Good luck and excuse my bad English.

hey! Listen carefully, I mean, read carefully. the rule is simply as follows: الألف و السين و التاء تعني الطلب أ، س ، and ت , when they are together in a verb like استبدل , mean الطلب asking, requesting,...etc. بدَل means that someone change something without the help of others or the others are not important in this situation. استبدل means that you ask some one to change something and they change it. others examples: أطعم means ( to feed ) استطعم means ( to ask for food ) there are some verbs where the أ، س and ت are a part of the verb, which means that they don't give the meaning of asking or requesting. To illustrate this, the verb استقبل the first three letters are a part of the verb and the verb without them means a different thing.