Another obstacle was the grammatical construction of Siddo. Consider the tense system. Instead of inflecting a verb or using an unattached particle to indicate the past or future, Siddo used an entirely different word. Thus, the masculine animate infinitive dabhumaksanigalu'ahai, meaning to live, was, in the perfect tense, ksu'u'peli'afo, and, in the future, mai'teipa. The same use of an entirely different word applied for all the other tenses. Plus the fact that Siddo not only had the normal (to Earthmen) three genders of masculine, feminine, and neuter, but the two extra of inanimate and spiritual. Fortunately, gender was inflected, though the expression of it would be difficult for anybody not born in Siddo. The system of indicating gender varied according to tense.

All the other parts of speech: nouns, pronouns, adjectives, adverbs, and conjunctions operated under the same system as the verbs.