I would like to try to propose a potential novel terminology for a motif found in several languages. The following is a short description of the idea.

Phonosemantic Duplication is a linguistic phenomenon where words that represent duplicity, duality, or redundancy exhibit clear internal phonetic repetition.

for example 

Words for "Twin": 

Greek: Δίδυμος (Didymos) {Di Di} 

Hindi: द्वंद्व (Dwandwa) {Dwa Dwa} 

Yoruba: Ibeji {E,E,E}

Bengali: যমজ (Yamaja) {Ya Ya} 

Words for "Same/Identical": 

Burmese: တန်းတူ (tanta) {Ta Ta} 

Indonesian/Malay: sama sama {Sama Sama} 

Malayalam: സമാനമാന (samanaman) {aman aman} 

Words for "Redundancy": 

English: Redundant {Dun Dun}

Haitian Creole: nesesè {Se Se} 

Lao: ຊໍ້າຊ້ອນ (soason) {So So}

The concept highlights the relationship between sound and meaning, showing how phonetic structures can reinforce semantic concepts in language. Unlike "reduplication," which is a broader term for repeated syllables in words (e.g., "bye-bye"), Phonosemantic Duplication specifically involves words that inherently represent duplicity or duality.

Onomatopoeia mimics sounds (e.g., "buzz" or "sizzle"), but Phonosemantic Duplication focuses on the repetition within words that convey the idea of being doubled or identical. 

Echo words, like "shush" or "choo-choo," repeat sounds for emphasis, whereas Phonosemantic Duplication emphasizes the semantic meaning through repeated phonetic structures.

Phonosemantic Duplication is distinct from reduplication, onomatopoeia, and echo words, offering a unique perspective on the interplay between sound and meaning in language. This concept adds a new idea to linguistic studies, highlighting the intricate connections between phonetics and semantics.