If you already speak Russian, most probably, wrong stress in words has let you down. You've learned a written word by heart and understand its meaning for sure but when you say it out loud – for some reason nobody understands you. Or your phrase has seemed to be funny for your interlocutors. So what's wrong? It's all homographs – words which are spelled the same way, but change their meaning according to a stress.
Russian-speaking people are not always on friendly terms with stresses, too, but it mostly concerns the cases when stress in a word has been shifted to another syllable throughout the history, so that now there are two conventionally acceptable options (as in the word "одновременно" [adnavrimena] – simultaneously). There are also some sore points when many people put stresses incorrectly and it has become a habit (as in the words "каталог" [katalog] (catalogue), "торты" [torty] (cakes), "красивее" [krasivie]). But only foreigners make mistakes in the usage of homographs. Anyway, practice helps to avoid these mistakes.
It's no big deal, if you turn a castle (замок [zamok]) into a lock (замок [zamok]). There are still funnier coincidences. For example, with the verb (let’s say verbs as we are talking about several words) "писать" [pisat’]. If you leave your friends in order to work on your short novel, you put the stress in the word “писать” on the letter "a" (meaning – to write). When you put the stress on the letter "и", you express your intention to visit lavatory.
There are four groups of homographs which can conventionally be presented in the following examples:
1. Noun + the same noun.
Сила морской волны способна разрушать. – Force of sea wave can be destructive.
Волны мирно плескались за бортом. – Waves were quietly plashing outboard.
2. Noun + another noun.
На картине изображен средневековый замок. – There is a medieval castle in the picture.
Замок заржавел и не открывался. – The lock was rusty and didn't work.
3. Noun + adjective.
Звенит звонок, и ученики спешат в кабинет. – The bell is ringing and students are getting a move on a classroom.
Голос молодого певца звонок и прекрасен. – The young singer's voice is clear and beautiful.
4. Contextual homographs.
Мы сейчас в гостях у Вали. – Now we are at Valya's home.
Вали деревья, руби дрова! – Fell trees, chop wood!