Yorkshire in general is fairly safe. But like many places in the north of England, the collapse of various industries in Yorkshire has had a devastating effect on the economy, thus crime rates have become very high in some areas, mostly due to high unemployment. It's very unlikely that tourists will be victims of crime, but you should keep your wits about you if you decide to venture into areas that aren't tourist oriented.
Out in the countryside there is little risk of crime other than valuables left on view in cars in isolated places, though if going walking in winter take sensible precautions against the weather (http://www.bbc.co.uk/weat...). Also make sure you have a map and compass if you decide to go off the beaten track, you can very easily get lost without them.
In towns and cities, keep valuables out of sight, and stick to well-lit busy areas at night as is recommended for all UK towns and cities.
talk
Generally, Yorkshire folk speak quite understandable English, and even many dialect speakers have a "posh voice" that they can put on for tourists; however, some phrases may catch you out.
Owt or nowt - means anything or nothing both words can be used separately.
Love - is used when greeting "Hi love" or "Yes love"
Snicket/Ginnell - The former is a covered alley, the latter an uncovered one. E.g. 'I heard him racing down the snicket!'.
There are also words like "hither" "sethee" "thee" "thine" "thy" "duntha" and numerous others and if spoken as dialect is very difficult to understand by people from outside the region.
Some small industrial towns in West and South Yorkshire may be more difficult to understand. However, these are not popular tourist venues.