Reduplication

Tengthah-suu (重疊辭 ;  reduplication )

koaan, koankoaan, koaarn'koankoaan

Duples (A'A)

You can repeat monosyllable A to get A'A, for some emphasis, to mean "quite" or "very".

• loaxnloan (亂亂 ;  q. disorderly; chaotic )
• hoanhoafn (番番 ;  q. uncivilized; rude; unreasonable )
• koankoaan (懸懸 ;  q. high; tall; elevated )
• oarn'oaxn (怨怨 ;  q. loathed; hated )
• boafnboarn (滿滿 ;  q. full of; brimming with )
• thoatthoad (脫脫 ;  q. separated; broken away from )
• boadboat (沫沫 ;  q. foamy; sudsy )

Triplication

You can repeat a syllable A three times (A"A'A) to mean extremely A. Generally, the first syllable undergoes tone change to the rare rising tone (#6; see Tones of Taiwanese).

• aarng'ang'aang (紅紅紅 ;  x. aang - red etc )
• jiirn'jinjiin (仁仁仁 ;  x. jiin - firm & full )
• koaarn'koankoaan (懸懸懸 ;  x. koaan - tall etc )
• loaan'loaxnloan (亂亂亂 ;  x. loan - disorderly; chaotic )
• kaao'kauxkau (厚厚厚 ;  x. kau - thick etc )
• zeerng'zexngzeng (靜靜靜 ;  x. zeng quiet )
• kiirm'kimkym (金金金 ;  x. kym - golden) )
• khuiie'khuikhuy (開開開 ;  x. khuy - wide open )
• thoor'thothoo (塗塗塗 ;  x. thoo - in shambles & completely lost )
• kaao'kaokaux (夠夠夠 ;  x. kaux - sufficient (cf. kaokaux) )
• siirn'sirnsixn (信信信 ;  x. sixn - believing without doubt )
• kof'kofkor (古古古 ;  x. kor - ancient )
• leerng'lefnglerng (冷冷冷 ;  x. lerng - cold; cool )
• seek'segsek (熟熟熟 ;  x. sek - commonly seen; acquainted with )
• took'togtok (獨獨獨 ;  x. tok - alone )
• siaap'siapsiab (澀澀澀 ;  x. siab - bitter; astringent )
• siip'sipsib (溼溼溼 ;  x. sib - moist (cf. sipsib) )

Zhamkhør

• http://www.edutech.org.tw/Composition.htm
• niaxnia (is this reduplication?)