My first experience with a car navigator was a simple device that spoke a limited number of fixed phrases only. This meant that it did not say street names at all. The next navigator was a pleasant surprise in its ability to say the names rather well—but at the cost of breaking Finnish grammar. For example, it says Käänny tielle Vaasankatu, “turn to Vaasankatu”, literally “Turn to road Vaasankatu”, instead of the correct Käänny Vaasankadulle. The reason is obvious: implementing inflection of street names would require extra work, even though only one case form, the allative, would be needed. Since most languages do not have such problems, inflection was not implemented in the software.
An expression like tielle Vaasankatu can be regarded as ungrammatical, but it is understandable. I must confess that I have used a similar trick in a localization project: phrases of the form “from A to B”, where A and B are names of locations, had to be translated as kohteesta A kohteeseen B, instead of the correct A:sta B:hen.
The Finnish version of Facebook uses the message pattern Tänään on henkilön NN syntymäpäivä (Today is the birthday of person NN). This is unnatural, but apparently unavoidable. Using appropriate expressions like Tänään on Matti Meikäläisen syntymäpäivä would require the ability to form the genitive of any name, and this would be very difficult to do completely correctly, due to irregularities and the possibility of foreign-language names.