Correct spelling for the English word "most lotsa" is [mˈə͡ʊst lˈɒtsə], [mˈəʊst lˈɒtsə], [m_ˈəʊ_s_t l_ˈɒ_t_s_ə] (IPA phonetic alphabet).
"Most" is derived from the Old English word "mǣst", which means "greatest" or "highest degree". It has remained relatively unchanged in its meaning throughout history.
However, "lotsa" is an informal, colloquial contraction of "lots of". The term "lots" can be traced back to the Old English word "hlot", which originally meant a random selection or portion. Over time, its meaning expanded to refer to a large quantity or a great number of something.
Therefore, when combined, "most lotsa" does not have a specific etymology as it is simply a blend of these two words, incorporating informal language usage.