"I am learning Portuguese little by little."
Translation:J'apprends le portugais petit à petit.
Unlike English, definite articles (le,la,l',les) are used with titles, languages academic subjects.
However, only in the phrase "to speak + language" can you use both forms, with or without le.
Il parle portugais. / Il parle le portugais.
He speaks Portuguese.
What part of speech is "petit à petit"? Adverb? (Reverso lists it as an adverb. http://dictionary.reverso.net/french-english/petit%20%C3%A0%20petit)
My reason for asking is I thought that usual placement of French adverbs is right after the verb they are modifying.
Is this a special case?
It is an adverbial expression which may affect its placement. Remember that long adverbs often begin or end a sentence.
Généralement, je me réveille à 7 heures.
Je me promène dans le parc à l'heure du déjeuner quelquefois.