It depends more on the intent not on the words...
few examples:
1) A pandit mocked at an illiterate chanting mara prabhu: from vishnu sahasranama and circambulating the trees ( in tamil mara means tree) When asked about the meaning he replied: Lord of trees. Pandit laughed at him and he corrected it saying it is not mara prabhu: but amara prabhu:.
Illiterate felt very sad that day. Immediately the pandit had a dream who asked you to correct him, the matter / dealing is between him & me... Who are you to interfere?
Bhaavam & bhakti is very much important rather than the words.
Hearsay is that this story related with pandit to be bhattatri & the illiterate as poonthanam.
2) when i say शुभं भूयात् in a normal way the meaning is same. When I stress ( out of jealousy, burning with anger inside) and say शुभं भूयात् , the meaning is just the opposite.The intent is different