Greek εὐθὺς ('immediately') is a single adverb, as is Latin continuo; the Peshitta renders the notion periphrastically with ܒܪ ܫܥܬܗ ('in that hour/moment', literally 'son of his hour'), a Semitic idiomatic construct phrase for instantaneity.
EN Immediately the father of the child cried out with tears, “I believe. Help my unbelief!”
ES Y luego el padre del muchacho dijo clamando: Creo, ayuda mi incredulidad.
ZH-HANS 孩子的父亲立时喊着说 :「我信!但我信不足,求主帮助。」
ZH-HANT 孩子的父親立時喊着說 :「我信!但我信不足,求主幫助。」
Greek εὐθὺς ('immediately') is a single adverb, as is Latin continuo; the Peshitta renders the notion periphrastically with ܒܪ ܫܥܬܗ ('in that hour/moment', literally 'son of his hour'), a Semitic idiomatic construct phrase for instantaneity.
Greek supplies the definite article ὁ πατὴρ and Latin omits it as Latin lacks articles; the Peshitta ܐܒܘܗܝ incorporates a pronominal suffix ('his father'), an anticipatory possessive idiom not explicit in the Greek or Latin.
Greek and Latin use the preposition μετὰ / cum ('with') governing the noun 'tears'; the Peshitta instead employs the subordinating particle ܟܕ ('while/when') introducing the verb ܒܟܐ ('he wept'), recasting the prepositional phrase as a temporal circumstantial clause.
Greek δακρύων and Latin lacrimis are genitive/ablative plural nouns ('tears'); the Peshitta uses the finite verb ܒܟܐ ('he wept'), a construction shift from nominal to verbal expression consistent with the preceding ܟܕ clause.
Greek πιστεύω and Latin Credo are single first-person finite verbs; the Peshitta renders the present with the participle plus independent pronoun ܡܗܝܡܢ ܐܢܐ ('believing I-am'), the standard Syriac periphrastic present-tense construction.
Greek frames the object as a dative of the abstract noun 'with my unbelief' (μου τῇ ἀπιστίᾳ) and Latin as accusative incredulitatem meam; the Peshitta uses a genitival construct ܠܚܣܝܪܘܬ ܗܝܡܢܘܬܝ ('the deficiency of my faith'), making explicit a 'lack of faith' rather than a simple privative noun.