notadictionary.com
あ、もしもし?お母さんだけどいまダイソーなんだけどさぁ…
→ “Oh, hello? It's Mom, but I'm at Daiso right now...”
あ a = oh (interjection expressing realization or surprise)
もしもし moshimoshi = hello (greeting used when answering the phone)
お母さん okaasan = mom (nursery term for mother)
お o = honorific prefix
母 ha = mother
さん san = honorific suffix
だけど dakedo = but / however (conjunction indicating contrast or explanation)
いま ima = now (adverb indicating current time)
ダイソー daisō¹ = Daiso (loanword from 'Dollar Store', a popular Japanese retail chain)
なんだけど nan dakedo = it is... but (colloquial contraction of 'na no' + 'dakedo')
さぁ saa = well... (sentence-final particle expressing hesitation or trailing off)