Translation:The phones are available
Let's see. Well, 'zi' is the subject particle (plural 3rd person noun from n-n class), 'na' is the time particle (present tense) and 'patikana' is a verb (to be found or to be available). Kupatikana is kinda interesting because it shows that verbs in Swahili verb can have compound forms. Kupata means to get. Then you add in the "-ik" to make the verb become stative and the '-na' at the end makes it reciprocal as well. Therefore, you move from kupata (to get) to kupatikana (to be available).
Why does it have to have a reciprocal affix? Wouldn't "Simu zinapatika" (without "-na") mean Phones are available?
I saw another example of an unexpected reciprocal being added to a word in the stative verbs unit: inawezekana (it is possible). Is this a common form in Swahili? What function does it serve?
I am a native speaker in the Tanzania mainland. Zinapatika is commonly used in some part(s) in Zanzibar( I heard it in Rural Unguja). Not sure about Inawezeka though, seems way too weird. But I advice you always should use the whole word, finish up to the 'na'. That is the way used by majority of swahili speakers.
I hope this explanation will suffice. If the verb kupenda means to love, then the verb kupendana means to love (one another). Notice that the verbs meaning barely changes and that seems to be true for most verbs. Some verbs meaning can change like kulala, meaning to sleep, to kulalana which means either to sleep with each other or to have sex. Reciprocal verbs can be used in the singular tense, but they make more sense in the plural tense. Hope the examples aren't too crude...
Wanapendana -- They love each other. Tukiongeana tungekuelewana -- If we talked to each other, we would understand each other. Kama tunapendana, basi tunaweza kunalalana. -- If we love each other, then we can sleep with each other.