What is the test for determining whether a defendant is entitled to a fair trial for using an offensive language in a criminal offence?

" '[W]hen language which is reasonably susceptible of two constructions is used in a penal law ordinarily that construction which is more favorable to the offender will be adopted. [p] The defendant is entitled to the benefit of every reasonable doubt, whether it arise[s] out of a question of fact, or as to the true interpretation of words or the construction of language used in a statute.' " (People v. Davis (1981) 29 Cal.3d 814, 828, 176 Cal.Rptr. 521, 633 P.2d 186, quoting In re Tartar (1959) 52 Cal.2d 250, 256-257, 339 P.2d 553.)