It is not a condition for one who wants to embrace Islam to utter this particular shahada statement or testification of faith. It is enough for one to utter a statement that gives its meaning. For example, one may say:
Uttering one of these statements is sufficient for one to embrace Islam. However, the term “ash-hadu” is better than other terms, because its linguistic meaning includes the knowledge, belief, and declaration. By using the term ‘ash-hadu’, one confirms the meaning in a way that is not attained using other words.
Darulfatwa 2022