Thailand's economic growth likely slowed sharply in the second quarter, while the economy contracted on a quarterly basis, a Reuters poll of economists showed, as subdued household consumption offset support from exports and private investment. Southeast Asia's second-largest economy likely expanded 1.7% in the April-June quarter from a year earlier, slowing from 2.8% growth in the previous quarter, according to the median estimate in an August 7-12 poll of 15 economists.