Onomatopoeic words are called “अनुकरणात्मक शब्द” (anukaranatmak sabda) in Nepali. These words function like adverbs. Here are some such words that are pretty common. Also, some of the words like ‘chittika’ are not really the ‘sound’ concept (like: knock-knock) but more of a different concept of ‘being X’ or ‘X to happen’. :
Dropping Sound: खत्रक्क (khatrakka)
It is like ‘bam’ on the ground.
टेबलबाट कलम खत्रक्क खसेको मात्र थियो, फुटिहलेछ (Tebal bata kalam khatrakka khaseko matra thiyo, phutecha)
=The pen had just fallen from the table when it cracked!
To Be Clean: चिटिक्क (chitikka)
It means ‘to be made/ cleaned nicely, so it appears good/ clean’
उसले उसको कोठा चिटिक्क मिलायो (Usle usko kotha chitikka milayo)
=He cleaned (made) his room.
The sound of water splash: छयाप्प (chyappa)
The name says it all. It’s like ‘drenched!’
रामले मलाई पानी छयाप्प हान्यो (Ram le malai pani chyappa hanyo!)
=Ram threw water at me (making me wet!)
Waking up: जुरुक्क (jurukka)
It means like ‘To wake up suddenly or at once’
आज म बिहान जुरुक्क उठेको ! (Aja ma bihaana jurukka utheko!)
=I woke up in the morning effortlessly!
Tightness (on the body): टिमिक्क (timikka)
Applicable only to apparels.
शरीरमा टिमिक्क हुने लुगा किन किनेको त ? (Sharir ma timikka hune luga kina kineko ta)
= Why did you purchase clothes which is too tight-fitting for you?
To walk: ठमठम (thamtham)
It has a meaning like ‘to walk strongly unaided’
बुढो अहिले सम्म ठमठम हिड्ँछ (budho ahile samma tham tham hidcha)
= The Old guy still walks like in his prime!
The sound of being hit; Being full: ड्याम्म (dyamma)
खाजा खाएर पेट ड्याम्म भइसक्यो (khaja khaera pet dyamma bhaisakyo)
= My stomach is full after eating the lunch.
There are still so many Onomatopoeic sounds in Nepali, but this is enough for today.
Have a good day!