Anywhere west of Nagoya, you'll find dialects of Japanese that differ from so-called "standard Japanese." Peter Tse notes that "broadly speaking, the main differences between Western [hougen / dialects] and Eastern Japanese can be summarized in seven points."
1. Negative verbs end in nai in the east, but in hen in the west. For example, 寿司を食べない becomes 寿司を食べへん。The same with courteous forms: 食べません becomes 食べまへん。However, my sources say that in Kagawa prefecture, the -hen ending is not used in its full form. You are more likely to hear 「寿司、食べん」。So, in Kagawa, tabehen becomes taben.
2. In the past tense, verbs end in -nakatta in the east, but -henkatta in the west. For example, 寿司を食べなかった becomes 寿司を食べへんかった。
3. In Tse's words, "The past tense of Eastern Japanese has a double 'tt' sound, but Western Japanese frequently has a single "t" sound instead, sometimes accompanied by a long vowel sound like 'ou.'" So, Western Japanese does not form crisp double consonants. For example, そうだ思った becomes そうだ思うた。
4. The verb "to be" for animals and people is iru in the east, but oru in the west. For example, 人がいる becomes 人がおる。
5. The copula da in the east is ya (in Kansai) or ja (in Chuugoku). For example, そうなんだ becomes そうなんや or そうなんじゃ。
6. The adverbial form of adjectives ends in -ku in the east, but usually lacks -ku in the west. For example, 早く食べる becomes はよう食べる。
7. The imperative form of verbs in the west can differ from those in the east, but both forms are commonly used in the west. For example 早く食べろ can become はようたべえ。
I'm told that you don't need to be able to speak in the dialects to communicate. Everyone I've talked to has said that it's not important because you can use "standard Japanese." However, you will likely often hear dialects in west Japan. Moreover, I think it's important to learn a few things about local language.