High priority means you must incorporate the requirement in the next product release. Medium priority means the requirement is necessary but you can defer it to a later release if necessary. Low priority means it would be nice to have, but you might have to drop it because of insufficient time or resources. The reader of a requirement statement should draw only one interpretation of it. Also, multiple readers of a requirement should arrive at the same interpretation.
Natural language is highly prone to ambiguity.
Write each requirement in succinct, simple, straightforward language of the user domain, not in technical jargon. See whether you can devise tests or use other verification approaches, such as inspection or demonstration, to verify that the product properly implements each requirement. If you can t verify a requirement, determining whether or not it was correctly implemented is a matter of opinion. Requirements that aren t consistent, feasible, or unambiguous are also not verifiable. Any requirement that the product shall support something isn t verifiable.