Testimony
Part of speech: noun
Definition: Statements made by a witness in court. An account of first-hand experience. In a church service, a personal account, such as of one's conversion.
Example sentence: Every decently-made object, from a house to a lamp post to a bridge, spoon or egg cup, is not just a piece of 'stuff' but a physical embodiment of human energy, testimony to the magical ability of our species to take raw materials and turn them into things of use, value and beauty.
Testimonial
Part of speech: noun
Definition: A statement, especially one given under oath; testimonyA written recommendation of someone's worth or characterA tribute given in appreciation of someone's service etc.A match played in tribute to a particular player (who sometimes receives a proportion of the gate money).
Example sentence: I think even if I did the research mentioned above, it would be a total waste of money because if those people don't believe in the testimonials, they won't believe in the research at all. They would say that I made it all up. So why waste money?