Sentence:  No verses can be more <WSD>mellifluous</WSD> than Petrarch's: something of this will perhaps be attributed to the softness of the Italian language; but the English tongue is also capable of it, however obstinately Johnson may have pronounced otherwise. 
Meaning of the word marked with <WSD> tags:  Sweet, smooth and musical; pleasant to hear (generally used of a person's voice, tone or writing style).