NHK: In most cases...however and nevertheless/still can be used interchangeably...meaning...can completely replace each other...but...they are Grammatically... there is still a little difference... nevertheless will be used when... it is inconsistent with the previous text... it is often said in English however = but... and however is in addition to the previous text... There will still be some reasons not mentioned before...so...the same sentence...in certain situations...however or nevertheless...may have slightly different meanings...maybe To put it another way... nevertheless = in spite of... and however = in spite of + on the other hand... There is also a special usage... that is when comparing the previous article... nevertheless / nevertheless "Nevertheless" tells you that the following information is surprising in view of the previous information..."However" does not have this connotation of unexpectedness.. .for example..."Japanese is a very difficult language. Nevertheless she spoke it quite fluently after only 6 months in Tokyo."...in this example..."However" can be adapted too.....BUT ....."Japanese is a very difficult language. However we can drop it in the second year."...Nonetheless / Nevertheless cannot be adpated to replace "However" in the second example as there is no surprising information.. ........