All of my Japanese teachers have told me that な-adjectives converted to に-ending words and い-adjectives converted to く-ending words, when followed by a verb, are 'adverbs'. However, sentences sound ridiculous when translated in keeping with this principle:
'I want to eat lunch quietly.' or
'I want to eat a quiet lunch.'
'Be quiet!' or
'What's with you saying so many damn dirty things? Are you being stinky?' or
'What's with you saying so many damn dirty things? Are you being stinkily?' (Obviously, stinkily isn't a word... but...)...
Is there any way I can accommodate my academic learning and my true-to-life experience simultaneously, or do I have to surrender one of them for the other?
Also, can you pay especially close attention to the first sentence? I'm a little sad that I haven't been able to find the words that mean 'a quiet lunch'. Alongside the first sentence in this post,
静かな場所でランチが食べたいです is a considered alternative, but it means, 'eat lunch in a quiet place'. This doesn't comprise the implied 'peace of mind' that 'a quiet lunch' retains in English.