Final answer:
Helen Keller tried to say her first word when she was 6 months old, and it was 'doll'.
Step-by-step explanation:
Helen Keller tried to say her first word when she was 6 months old. According to the given information 'When I had played with it a little while, Miss Sullivan slowly spelled into my hand the word 'd-o-l-l.' I was at once interested in this finger play and tried to imitate it.' This shows that the first word Helen tried to say was 'doll'.