testify

Testify is the act of giving evidence or sworn statements about facts relevant to a legal matter or inquiry. A person who testifies is a witness. Testimony may be oral, in court or at a deposition, or written, as an affidavit or sworn declaration. Fact testimony describes observed events; expert testimony provides specialized opinions based on expertise.

Before testifying, a witness typically takes an oath or affirmation to tell the truth. In many jurisdictions, testimony is subject to cross-examination, allowing opposing parties to challenge memory, accuracy, and credibility. The judge determines admissibility under evidentiary rules that limit hearsay and protect privileges. Testimony can be impeached for bias or inconsistency.

Testimony helps establish facts, corroborate evidence, or explain complex points. Its weight depends on credibility, relevance, and corroboration. In civil cases, the burden of proof is usually preponderance of the evidence or a clear and convincing standard, with testimony contributing to the determination.

In criminal cases, the standard of proof is higher, and safeguards aim to prevent coercion and unfair prejudice. Legal systems also recognize privileges that shield certain communications from being used as testimony, such as attorney–client or spousal privileges, along with protections against compelled self-incrimination in some jurisdictions.

Outside courts, testimony can refer to statements about personal beliefs or experiences, such as a religious or personal testimony recounting an experience or advocating a view.