[tarvaina]

As a Finnish speaker I've often wondered about this. In Finnish (and Hungarian) the stress is almost always on the first syllable, so it is easy for speakers to distinguish word boundaries. How do speakers of other languages do it?

Now I'm wondering if the first consonant is lengthened in Finnish too or if the syllabic stress makes it unnecessary.

[nine_k]

Japanese: there's no stress, all syllables are the same length, except there are explicitly lengthened vowels which are semantically different and can occur almost in any position in a word. A syllable ends with a vowel or with "n", and there are no consonant clusters at the beginning of a syllable. There can be "long" consonants but they are always on the split between syllables, always inside a word, and actually make recognizing the boundaries easier. Usually it's easy enough to just listen to the sequence of syllables and cut it into probable words. Regular grammatical markers (particles that represent grammatical roles, endings of verbs and adjectives, which are also basically verbs) usually give enough structure to split ambiguous combinations correctly. (Not a native speaker.)

Spanish: most words are reasonably short, grammatical features like the articles and the endings of nouns / adjectives / verbs intersperse the speech all the time and give you clues where a word may begin, and what kind of word. The stress is not very regular but the very irregularities have some internal patterns. You only need a pretty short syllable buffer before a word can be recognized unambiguously, and the rest of it mostly predicted, except maybe for the ending, but you know which kind of ending it may be. Even if you don't know a word, it's easy to see its boundaries and its grammatical role. If the words were as long and grammatically varied as Finnish, this could become much harder! (Not a native speaker.)

English has a lower contrast between vowels than Spanish, it's easier to mishear a word, and harder to recognize it in slightly distorted forms, like singing. Again, the articles and, to some extent, the verb endings, help recognize some boundaries, but less efficiently. Many of the most frequent words only have one or two syllables though (like "blue" or "open"). Most really long words are recognizable as a single word long before they end (like "discombobulated"), they rarely sound like shorter unrelated words glued together. The sheer amount of daily training as a speaker, and predictability of most words in a sentence, still allow to speak and understand English at a very high speed. Intonation sometimes helps, too.

[retrac]

About half of English words are one syllable long and most of the rest are two. If it's stressed, it's probably a word.

Stress placement on disyllabic words works at a grammatical level, not just a phonetic one. "To record" and "a record" (reCORD, REcord) have different stress placement because of their grammatical roles (noun/verb).