Calling d3.locale() doesn't change the internal workings of d3, it just creates and returns a localization object. You need to capture this return value and store it in a variable so you can use it later. Given the object you created in your example code, you could do that like this:

var RU = d3.locale(ru_RU);

Then when you need a value to be localized, you must call for it explicitly. In your case, you want the full month names to be displayed as x-axis labels.

To do this, you can add a .tickFormat() to your x-axis, and specify that the format should be your localized version of a full month name.

var xAxis = d3.svg.axis()

  .scale(x)

  .orient(bottom)

  .ticks(5)

  .tickPadding(8)

  .tickFormat(RU.timeFormat(%B));

locale.timeFormat() is equivalent to d3.time.format(), except that it uses the locale that you created instead of defaulting to en_US. In this case locale is the variable RU which we created earlier.

Here is the updated JSFiddle.

Remember, each time you want a localized string or value, you need to call for it explicitly. Use locale.numberFormat() in place of d3.format(), and locale.timeFormat() in place of d3.time.format(), where locale is a localization object created with d3.locale(). Hope that helps.