How is "Ashhadu an la ilaha illa Allah" correctly pronounced, and is it sufficient to pronounce it with the addition of "annahu"?

Saying, "I bear witness that there is no god but Allah," is sufficient. This is because the original form of the softened "an" (أَنۡ) is the emphasized "anna" (أَنَّ), and it has been softened and its subject omitted. This is supported by its occurrence in some hadiths, such as the hadith narrated by Al-Tabarani in Al-Kabeer from Umair ibn Wahb, who testified with this wording in the presence of the Messenger of Allah, peace and blessings be upon him.