"I continue reading."
Translation:Saya melanjutkan membaca.
Melanjutkan and meneruskan are synonyms. Melangsung does not exist, the word langsung is usually paired with the suffix -kan when making it a verb. And melangsungkan is not exactly the same with melanjutkan or meneruskan.
Melanjutkan/meneruskan = to continue something that has already been started. Melangsungkan = to conduct something, to initiate something. It's usually used to say to conduct some kind of events like ceremonies festivals, etc.