Plain Language in Government Communications Act of 2008 - (Sec. 4) Requires each executive agency, within one year, to: (1) use plain language in any covered document issued or substantially revised after the date of the enactment of this Act; and (2) use the English language in covered documents when appropriate. Authorizes agencies to: (1) use plain language in any revision of a covered document issued on or before such date; and (2) follow the guidance of the Plain English Handbook published by the Securities and Exchange Commission (SEC), the Federal Plain Language Guidelines, or their own plain language guidance as long as it is consistent with such Handbook, Guidelines, and the Comptroller General's recommendations.
Declares that nothing in this Act shall be construed to: (1) prohibit the use of a language other than English; (2) limit the preservation or use of Native Alaskan or Native American languages; (3) disparage any language or discourage any person from learning or using a language; (4) affect protections regarding language access; or (5) be inconsistent with the Constitution.
Defines "covered document" to include: (1) any document relevant to obtaining a benefit or service or filing taxes; and (2) a letter, publication, form, notice, or instruction, in paper or electronic form, but not a regulation.
Requires agencies to use plain language in any collection of information.
Requires the Administrator of the Federal Aviation Administration (FAA), acting through the Plain Language Action and Information Network, and the SEC to report to specified congressional committees on whether the Comptroller General's recommendations about plain language guidelines and best practices have been incorporated into the Federal Plain Language Guidelines and the Plain English Handbook and, if not, why.
(Sec. 5) Requires each agency head to report to specified congressional committees on how it intends to: (1) communicate the requirements of this Act to employees; (2) train employees to write in plain language; (3) meet the one year deadline; (4) ensure ongoing compliance with this Act; (5) designate a senior official to be responsible for implementing this Act; and (6) use plain language in promulgated regulations. Requires agency heads to report on efforts to meet such objectives and on compliance with this Act.
Requires the Comptroller General to evaluate existing guidance for agencies on writing in plain language and report to the Office of Management and Budget (OMB) and specified congressional committees on plain language guidelines and best practices.