The word ‘Solemnly’ is also read without sounding out the ‘n’, as in ‘SOLL-luhm-li’.

Note also that the 1st syllable is pronounced as ‘SOLL’ (rhyming with doll) and not ‘Soul’.

But you have to pronounce the ‘n’ in ‘Solemnise’ and ‘Solemnisation’.
 
For the verb ‘Solemnise’, you should say ‘SOLL-lem-naiz’ .

For the noun ‘Solemnisation’, you say ‘SOLL-lem-nai-ZAY-shuhn’.

Listen to this podcast to get the pronunciation right.

Source: Edited from the english@work e-newsletter by 938LIVE. Subscribe to the english@work newsletter.