The Collaborative International Dictionary of English v.0.48:

Speak \Speak\, v. i. [imp. Spoke(SpakeArchaic); p. p.
   Spoken(Spoke, Obs. or Colloq.); p. pr. & vb. n.
   Speaking.] [OE. speken, AS. specan, sprecan; akin to
   OF.ries. spreka, D. spreken, OS. spreken, G. sprechen, OHG.
   sprehhan, and perhaps to Skr. sph[=u]rj to crackle, to
   thunder. Cf. Spark of fire, Speech.]
   1. To utter words or articulate sounds, as human beings; to
      express thoughts by words; as, the organs may be so
      obstructed that a man may not be able to speak.
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            Till at the last spake in this manner. --Chaucer.
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            Speak, Lord; for thy servant heareth. --1 Sam. iii.
                                                  9.
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   2. To express opinions; to say; to talk; to converse.
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            That fluid substance in a few minutes begins to set,
            as the tradesmen speak.               --Boyle.
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            An honest man, is able to speak for himself, when a
            knave is not.                         --Shak.
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            During the century and a half which followed the
            Conquest, there is, to speak strictly, no English
            history.                              --Macaulay.
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   3. To utter a speech, discourse, or harangue; to adress a
      public assembly formally.
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            Many of the nobility made themselves popular by
            speaking in Parliament against those things which
            were most grateful to his majesty.    --Clarendon.
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   4. To discourse; to make mention; to tell.
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            Lycan speaks of a part of Caesar's army that came to
            him from the Leman Lake.              --Addison.
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   5. To give sound; to sound.
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            Make all our trumpets speak.          --Shak.
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   6. To convey sentiments, ideas, or intelligence as if by
      utterance; as, features that speak of self-will.
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            Thine eye begins to speak.            --Shak.
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   To speak of, to take account of, to make mention of.
      --Robynson (More's Utopia).

   To speak out, to speak loudly and distinctly; also, to
      speak unreservedly.

   To speak well for, to commend; to be favorable to.

   To speak with, to converse with. "Would you speak with me?"
      --Shak.
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   Syn: To say; tell; talk; converse; discourse; articulate;
        pronounce; utter.
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The Collaborative International Dictionary of English v.0.48:

Speak \Speak\, v. t.
   1. To utter with the mouth; to pronounce; to utter
      articulately, as human beings.
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            They sat down with him upn ground seven days and
            seven nights, and none spake a word unto him. --Job.
                                                  ii. 13.
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   2. To utter in a word or words; to say; to tell; to declare
      orally; as, to speak the truth; to speak sense.
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   3. To declare; to proclaim; to publish; to make known; to
      exhibit; to express in any way.
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            It is my father;s muste
            To speak your deeds.                  --Shak.
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            Speaking a still good morrow with her eyes.
                                                  --Tennyson.
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            And for the heaven's wide circuit, let it speak
            The maker's high magnificence.        --Milton.
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            Report speaks you a bonny monk.       --Sir W.
                                                  Scott.
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   4. To talk or converse in; to utter or pronounce, as in
      conversation; as, to speak Latin.
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            And French she spake full fair and fetisely.
                                                  --Chaucer.
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   5. To address; to accost; to speak to.
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            [He will] thee in hope; he will speak thee fair.
                                                  --Ecclus.
                                                  xiii. 6.
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            each village senior paused to scan
            And speak the lovely caravan.         --Emerson.
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   To speak a ship (Naut.), to hail and speak to her captain
      or commander.
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WordNet (r) 3.0 (2006):

speak
    v 1: express in speech; "She talks a lot of nonsense"; "This
         depressed patient does not verbalize" [syn: talk,
         speak, utter, mouth, verbalize, verbalise]
    2: exchange thoughts; talk with; "We often talk business";
       "Actions talk louder than words" [syn: talk, speak]
    3: use language; "the baby talks already"; "the prisoner won't
       speak"; "they speak a strange dialect" [syn: speak, talk]
    4: give a speech to; "The chairman addressed the board of
       trustees" [syn: address, speak]
    5: make a characteristic or natural sound; "The drums spoke"

Moby Thesaurus II by Grady Ward, 1.0:

256 Moby Thesaurus words for "speak":
   accost, acquaint, act for, address, admonish, advert to, advertise,
   advertise of, advise, affect, affirm, allege, allude to, announce,
   annunciate, apostrophize, appeal to, apprise, approach, argue,
   articulate, as it were, ask for, assert, assever, asseverate, aver,
   avouch, avow, bandy words, be in connection, be in contact,
   beat the drum, beg, bespeak, bespoke, betoken, blurt, blurt out,
   break silence, brief, bring word, buttonhole, call attention to,
   call to, cant, chatter, chew the fat, chew the rag, chin, chosen,
   colloque, colloquialize, colloquize, come out, comment,
   commerce with, commune with, communicate, communicate with, confab,
   confabulate, contend, converse, converse with, convey, deal with,
   declaim, declare, defend, deliver an address, demand, descant,
   dilate, dip, dip the ensign, disclose, discourse, discourse with,
   discuss, drawl, dress ship, emit a sound, engaged, enlighten,
   enunciate, examine, exchange colors, exclaim, expatiate, express,
   familiarize, figuratively speaking, flag, flag down, flash, gab,
   gasp, give a signal, give a talk, give notice, give the facts,
   give the nod, give voice, give word, glance, greet, hail,
   hail and speak, half-mast, halloo, have, have dealings with,
   have intercourse, have truck with, hoist a banner, hold,
   hold communication, indicate, influence, inform, insist, instruct,
   interchange, intercommunicate, interject, invoke,
   issue a manifesto, jargon, jargonize, kick, lay down, leave word,
   lecture, leer, let drop, let fall, let know, maintain,
   make a noise, make a sign, make a signal, make a sound, make known,
   make oneself heard, make reference to, manifesto, mention,
   mention to, mouth, mumble, murmur, muse, mutter, nod, noise, note,
   notify, nudge, observe, opine, patter, perorate, platform,
   plead for, poke, profess, pronounce, protest, put, put it,
   raise a cry, rebuke, recommend, refer to, reflect, remark, report,
   represent, reprimand, reprove, request, require, reserved, resound,
   reveal, salute, say, scold, selected, send word, serve notice,
   set aside, set down, shoot the breeze, shout, sign, signal,
   signalize, signify, so to speak, soapbox, sound, sound an alarm,
   sound the trumpet, speak fair, speak for, speak for itself,
   speak out, speak to, speak up, speak with, speechify, splutter,
   spout, stand for, stand on, stand up for, state, stick up for,
   stump, submit, support, symbolize, take a stand, take aside,
   take counsel with, take the floor, take the stump, talk,
   talk about, talk to, talk together, tell, touch, touch on,
   touch upon, traffic with, treat of, unfurl a flag, uphold, use,
   use language, utter, verbalize, verse, visit with, vocalize, voice,
   wag the tongue, warn, wave, wave a flag, wave the hand, whisper,
   wink