A Grammar and Dictionary of the Samoan Language, with English and Samoan vocabulary
The general rule is that the accent is on the penultima, but to this there are exceptions. Many words ending in a long vowel take the accent on the ultima; as maʻelega, zealous; ʻona, to be intoxicated; faigata, difficult. Verbs formed from nouns ending in a, and meaning to abound in, have properly two aʻs, as puaa (puaʻaa), pona, tagata, but page 3 are written with one. In speaking of a place at some distance, the accent is placed on the last syllable; as ʻO loʻo i Safotu, he is at Safotu. The same thing is done in referring to a family; as sa Muliaga, the family of Muliaga. So most words ending in ga, not a sign of a noun, as tiga, puapuaga, pologa, faataga, aga. So also all words ending in a diphthong, as mamau, mafai, avai.
In speaking the voice is raised, and the emphasis falls on the last word in each sentence.
When a word receives an addition by means of an affixed particle, the accent is shifted forward; as alofa, love; alofága, loving, or showing love; alofagía, beloved. Reduplicated words have two accents; as pálapála, mud; ségiségi, twilight. Compound words may have even three or four, according to the number of words and affixes of which the compound word is composed; as tofátumoánaíná, to be engulfed.
The articles le and se are unaccented. When used to form a pronoun or participle, le and se are contractions for le e, se c, and so are accented; as ʻO le ana le mea, the owner, lit the (person) whose (is) the thing, instead of O le e ana le mea. The sign of the nominative ʻo, the prepositions o, a, i, e, and the euphonic particles i and te, are unaccented; as ʻO i maua, ma te o alu ia te oe, we two will go to you. Ina, the sign of the imperative, is accented on the ultima; ína, the sign of the subjunctive, on the penultima. The preposition iá is accented on the ultima, the pronoun ia on the penultima.